(4√2)cos^2(15pi/8)-2√2

Question

(4√2)cos^2(15pi/8)-2√2

Answer 1

(4√2)cos^2(15pi/8)-2√2
(4√2)•(1+cos(15pi/4))/2-2√2
(4√2)•(1+√2/2)/2-2√2
2√2•(1+√2/2)-2√2
2√2•(1+2√/2-1)
2√2•2√2
√2•√2=2
Ответ:2