F(A)=3cosA+2sinA

Since cosA=-3/5 and sinA=4/5.

Substitution, F(A)=- 1/5

F(A)=√ 13sin(x+θ), where tanθ=3/2.

T=2π

x+θ=π/2+kπ

Axis of symmetry x=π/2-θ+kπ