cos(π/2 - x) = 1
cos(π/2) cos(x) + sin(π/2) sin(x) = 1
0 cos(x) + 1 sin(x) = 1
sin(x) = 1
x = π/2 + 2kπ, где k - целое число.
cos(π/2 - x) = 1
cos(π/2) cos(x) + sin(π/2) sin(x) = 1
0 cos(x) + 1 sin(x) = 1
sin(x) = 1
x = π/2 + 2kπ, где k - целое число.