Find the area of the region enclosed by the curve y=xsinx and the x-axis for 7π ≤x ≤8π .

2 answers

what's the trouble? Straightforward integration by parts:

∫[7π,8π] x sinx dx
= sinx - x cosx [7π,8π]
= (0-(8π)(1))-(0-(7π)(-1))
= -15π
What methods have you been taught for this kind of integration ?
Do you know how to do integration by parts ?