Question

вычислить не используя калькулятор
√2/2-(cos(pi/8)+sin(pi/8))^2

Answer 1

√2/2-(cosπ/8+sinπ/8)²=√2/2-(cos²π/8+2sinπ/8cosπ/8+sin²π/8)=
=√2/2-(1+sinπ/4)=√2/2-1-√2/2=-1;