f(x)=2(sinx)^2 +2sinx -1/2=2( sinx + 1/2)^2 -1min f(x) = f(π/6) = 2( 1/2 + 1/2)^2 -1 = 2-1 =1max f(x) =f(π/2) = 2( 1 + 1/2)^2 -1 = 9/2 -1 = 7/2
