Question

Найдите значение выражения

Answer 1

Если tg x = 1,6, то cos^2 x = 1/(1+tg^2 x) = 1/(1+2,56) = 1/3,56 = 100/356
sin^2 x = 1 - cos^2 x = 1 - 100/356 = 256/356
cos^2(pi/2 + x) = sin^2 x = 256/356
1 - sin^2 x = cos^2 x = 100/356
Получаем
sin^2 x/cos^2 x - 1/cos^2 x = 256/356 : 100/356 - 1/(100/356) =
= 256/100 - 356/100 = (256 - 356)/100 = -100/100 = -1