Power series diff. equation question

This one is obvious to do without power series, but I am wondering if there is a way to do this with power series.

cos(x)* y' + sin(x)*y =1

Use power series to prove that y(x)= sin(x) + c is the general solution to the differential equation.

Thanks.

This should help

http://www.stewartcalculus.com/data/CALC…

However, as it ends up, you've got the wrong solution. It actually comes out to
y = sin(x) + c*cos(x)

as you may verify.