I'm stuck on explaining this. Does anybody know how to help?(adsbygoogle = window.adsbygoogle || []).push({});

(a) By writing [tex]\cos^nx = cos^{n-1}xcosx [/tex] use integration by parts to show that

[tex] \int \cos^nxdx = \cos^{n-1}xsinx + (n-1) \int \sin^2xcos^{n-2}xdx. [/tex]

(b) Using the result of part (a) derive thereduction formula

[tex] n\int \cos^nxdx = \cos^{n-1}x\sinx + (n-1) \int \cos^{n-2}xdx. [/tex]

My Working:

(a) All i got so far is

u = cosx dv/dx =cos^{n-1}x

du/dx = -\sinx v = \int \cos^{n-1}x

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# Theoretical Integration

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