Integrate xsin(x) by parts between the limits of -pi/2 and +pi/2

Let u = x and dv/dx = sin(x),

By using the general expression of:

integral(u multiply dv/dx)dx = [u multiply v] - integral(v multiply du/dx)dx, and by realising that:

du/dx = 1, and v = -cos(x), we can deduce that the expression for integral(xsin(x)) becomes:

[-xcos(x)] - integral(-cos(x))dx, by putting the limits in, we can say that [-xcos(x)] is 0 because cos(-pi/2) = cos(pi/2) = 0. We can also say that, -integral(-cos(x))dx = [sin(x)], and by puitting the limits in this becomes [sin(pi/2) - sin(-pi/2)] = 2.

Therefore: integral(xsin(x))dx between -pi/2 and pi/2 = 2.

MB
Answered by Matthew B. Maths tutor

3582 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Using Discriminants to Find the Number of Roots of a Quadratic Curve


Why does a 'many to one' function not have an inverse?


At x=3, is the polynomial y= (4/3)x^3 -6x^2 + 11 at a maxima or minima?


What does it mean when I get a negative value when I do a definite integral?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning