Question

Для острого угла а найдите соs а, tg a, ctg a,если sin a 40/41​

Answer 1

sin a = 40/41

sin²a + cos²a = 1  =>

cos²a = 1 - sin²a,  

cos a = √(1 - sin²a)

cos a = √(1 - (40 / 41)²) = √((41² - 40²) / 41²) = √((1681 - 1600) / 41²) = √(81 / 41²) = 9/41

tg a = sin a/cos a = (40/41) / (9/41) = 40/9

ctg a = 1/tg a = 1 / (40/9) = 9/40