sedinalana

Verified answer

3^(-4cosx)=3^4sin2x
-4cosx=4sin2x
8sinxcosx+4cosx=0
4cosx(2sinx+1)=0
cosx=0⇒x=π/2+πn,n∈z
sinx=-1/2⇒x=(-1)^(k+1)*π/6+πk,k∈z