Integral 0 to pi tsin3tdtWhy is the uv parttcos3t3 have the

Integral 0 to pi tsin3tdt...Why is the uv part(-tcos3t)/3 have the limits also when you did not integrate it as it is the uv part,not the integral part...Forgive me for this is my first time seeing a problem where you have limits on 2 pieces. I though only the piece with the integral sign gets the limits..Thank You