Question

Найдите синус , косинус, тангенс, котангенс 22*30'

Answer 1

$22^{\circ} 30' = \dfrac{180^{\circ}}{8} = \dfrac{45^{\circ}}{2} \\ \\ sin \dfrac{45^{\circ}}{2} = \sqrt{ \dfrac{1 - cos45^{\circ}}{2} } = \sqrt{ \dfrac{1 - \dfrac{ \sqrt{2} }{2} }{2} } = \sqrt{ \dfrac{ \dfrac{ 2 - \sqrt{2 } }{2} }{2} } = \dfrac{ 2 - \sqrt{2} }{2} \\ \\ cos \dfrac{45^{\circ}}{2} = \sqrt{ \dfrac{1 +cos45^{\circ}}{2} } = \sqrt{ \dfrac{1 + \dfrac{ \sqrt{2} }{2} }{2} } = \sqrt{ \dfrac{ \dfrac{ 2 + \sqrt{2 } }{2} }{2} } = \dfrac{ 2 + \sqrt{2} }{2}$
$tg \dfrac{45^{\circ}}{2} = \dfrac{1 - cos45^{\circ}}{sin45^{\circ}} = \dfrac{1 - \dfrac{ \sqrt{2} }{2} }{ \dfrac{ \sqrt{2} }{2} } = \sqrt{2} - 1 \\ ctg \dfrac{45^{\circ}}{2} = \dfrac{1}{tg \dfrac{45^{\circ}}{2} } = \dfrac{1}{ \sqrt{2} -1} = \dfrac{1 + \sqrt{2} }{2 - 1} = 1 + \sqrt{2}$