# Y=XSIN(PI X)Y'=SIN(PI X)+ PI XCOS(PI X)I don't know who to solve for the critical numbers because I don't know how to factor this.Thanks!

With other problems such as Y= 2X^3 + 3X^2, I can easily factor the deriviate: Y'= 6X^2 + 6X and set it equal to zero. With the trig derivative, I don't know how to finish the problem...