A ∈ [0, Π / 2], then when ∫ (cosx SiNx) DX (upper limit a, lower limit o) takes the maximum, a=

A ∈ [0, Π / 2], then when ∫ (cosx SiNx) DX (upper limit a, lower limit o) takes the maximum, a=

∫[0→a](cosx-sinx)dx = (sinx+cosx)[0→a] = sina+cosa-1 = √2sin(a+π/4)-1
So when a = π / 4, take the maximum value √ 2-1