Question

$sqrt{2} *sin^2x( frac{pi}{2} +x)=-cosx$

Answer 1

√2cos²x+cosx=0
cosx*(2cosx+1)=0
cosx=0⇒x=π/2+πk,k∈z
cosx=-1/√2⇒x=+-2π/4+2πn,n∈z