I have been asked to explain without evaluating the integrals why(adsbygoogle = window.adsbygoogle || []).push({});

1) the integral of x cos x from 0 to pi/2 is positive and the integral of x cos x from pi/2 to pi is negative. And also would I expect x cos x from 0 to pi to be positive, zero or negative??? And why ???

2) to find the indefinite integral of x cos x dx and hence the exact values of values of x cos x from 0 to pi/2, cos x from pi/2 to pi and x cos x from 0 to pi?

Any help would be must appreciated. I know I haven't done anything so far so no need to have a go at me for it but I just wanted some help with it and even better the solutions obviously as this blimming thing is for in a few days time. Many thanks in advance

Nat

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# Why is this integral positive or negative

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