посчитайте вычеслить(cos15° + sin15°)²​

3/2 = 1. 5

cos(15)^2 + 2cos(15)sin(15) + sin(15)^2

=>

cos15^2 + sin15^2 = 1

=>

1+2cos15sin15 = 1+sin30

=>

1 + 1/2 = 3/2=1. 5