Find the solution of the differential equation #xy'=y+x^2\sinx# that satisfies the given initial conditions below?

#y(\pi)=0#

I know it's in #dy/dx+P(x)y=Q(x)# form, but what exactly is the integrating factor?

Like what is "exp" in #I=exp(\int P(x)dx)#?
(People use this a lot when mentioning the integrating factor, but I learned it as #I(x)=e^(\intP(x)dx)#...)