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.
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!
Ideas: Critical points are at y' = 0
Therefore, solving y' = sin(πx) + πxcos(πx) = 0 gives you the answer.
y'=sin(πx)+ πx cos(πx)
We want y' to be zero.
so sin(πx)+πx cos(πx) = 0
x = 0 is one answer. The other don't have analytic expressions so must be solved numerically.