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Evaluate\(\int\limits_{-\pi/2}^{\pi/2}\) x cos2x dx

Answer»

Let I =  \(\int\limits_{-\pi/2}^{\pi/2} \) x cos2x dx

f(x)=xcos2x

f(-x)=(-x)cos2(-x)

=-xcos2x

=-f(x)

 Hence, f(x) is an odd function.

Since, \(\int\limits_{-a}^af(x)dx=0\) if f(x) is an odd function.

Therefore, I = 0.



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