How do you differentiate f(x)=[sinx+tanxsincosx]3?

1 Answer
May 28, 2017

dfdx=3(sinx+tanxsinxcosx)2sinx(cosx+2)cos3x

Explanation:

To differentiate f(x)=[sinx+tanxsinxcosx]3,

we use chain rule and quotient rule.

Let f(x)=(g(x))3, where g(x)=sinx+tanxsinxcosx

Now as f(x)=(g(x))3, dfdg=3(g(x))2

and usiing quotient rule dgdx=sinxcosx×(cosx+sec2x)(sinx+tanx)(cos2xsin2x)sin2xcos2x

= sinxcos2x+sinxsecxsinxcos2xtanxcos2x+sin3x+sin2xtanxsin2xcos2x

= sinxcos2x+tanxsinxcos2xsinxcosx+sin3x+sin2xtanxsin2xcos2x

= 1sinx+1sinxcos3x1sinx1sinxcosx+sinxcos2x+sinxcos3x

= 1sinxcos3x1sinxcosx+sinxcos2x+sinxcos3x

= 1cos2xsinxcos3x+sinx(cosx+1)cos3x

= sinxcos3x+sinx(cosx+1)cos3x

= sinx(cosx+2)cos3x

and dfdx=dfdg×dgdx

= 3(sinx+tanxsinxcosx)2sinx(cosx+2)cos3x