sin(x0 = x - x3/3! + x5/5!..
sin(x2) = x2 - x6/2 + x10/4!
x2sin(x2) = x4 - x8/2 + x12/4!
The two terms (do the third as well) of the Maclaurin Series of x2sin(x2) can be integrated
The error is less than the next term's coefficient, so you need the 3rd term to bound the error.