Verified answer

Нужно знать:

1) sin(-α) = -sinα; cos(-α) = cosα;

2) sin0 = 0; sin(π/2) = 1; sinπ = 0; sin(3π/2) = -1;

3) cos0 = 1; cos(π/2) = 0; cos(2π) = 1.

Поэтому:

1) sin(-π/2) + cos(п/2) = -sin(π/2) + cos(π/2) = -1 + 0 = -1;

2) sin0 - cos(2п) = 0 - 1 = -1;

3) sinπ + sin(1,5п) = sinπ + sin(3π/2) = 0 + (-1) = -1;

4) sin0 + cos(2π) = 0 + 1 = 1.