Find the x values for stationary points in the curve y=3sin(2x) for 0<x<180

Firstly we differentiate the equation y=3sin(2x) w.r.t. x.By using the chain rule, we find the dy/dx=6cos(2x)Since a stationary point in the curve is a point where the gradient is 0, we can find them by finding the x values for when dy/dx=0.Therefore, 6cos(2x)=0cos(2x)=02x= cos^-1(0) since cos^-1(0)=90, 270 x=45, 135