Mengapa Nilai dari $cos165^{\circ }$ adalah $-\frac {1}{4}\sqrt {2}(1-\sqrt {3})$
Dalam matematika, trigonometri adalah cabang yang mempelajari hubungan antara sudut dan panjang sisi dalam segitiga. Salah satu fungsi trigonometri yang penting adalah kosinus, yang menggambarkan hubungan antara sudut dan panjang sisi yang berdekatan dalam segitiga. Dalam artikel ini, kita akan membahas mengapa nilai dari $cos165^{\circ }$ adalah $-\frac {1}{4}\sqrt {2}(1-\sqrt {3})$. Pertama-tama, mari kita tinjau sudut 165 derajat. Sudut ini terletak di kuadran II, yang berarti bahwa nilai kosinusnya akan negatif. Jadi, kita dapat mengeliminasi pilihan 1 dan 4, yang memiliki nilai positif. Selanjutnya, kita perlu mencari nilai eksak dari $cos165^{\circ }$. Untuk melakukan ini, kita dapat menggunakan rumus kosinus sudut setengah, yang menyatakan bahwa $cos(\frac{\theta}{2}) = \sqrt{\frac{1 + cos(\theta)}{2}}$. Dalam hal ini, $\theta = 330^{\circ }$, yang merupakan setengah dari sudut 165 derajat. Mari kita terapkan rumus ini untuk mencari nilai dari $cos(\frac{330^{\circ }}{2})$. Pertama, kita perlu mencari nilai dari $cos330^{\circ }$. Kita dapat menggunakan rumus kosinus sudut setengah lagi untuk mencari nilai ini. Dalam hal ini, $\theta = 660^{\circ }$, yang merupakan setengah dari sudut 330 derajat. Jadi, kita dapat menghitung nilai dari $cos(\frac{330^{\circ }}{2})$ sebagai berikut: $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(330^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1 + cos(660^{\circ })}{2}}$ $cos(\frac{330^{\circ }}{2}) = \sqrt{\frac{1