If f(x) =tan^2(x/2) f(x)=tan2(x2) and g(x) = sqrt(5x-1 g(x)=5x1, what is f'(g(x)) ?

1 Answer
Mar 16, 2016

f'(g(x))=tan(sqrt(5x-1)/2)xxsec^2(sqrt(5x-1)/2)

Explanation:

As f(x)=tan^2(x/2),

f'(x)=(d(tan^2(x/2)))/(d(tanx/2))xx(d(tanx/2))/(d(x/2))xx(d(x/2))/dx

Hence f'(x)=2tan(x/2)xxsec^2(x/2)xx1/2

or f'(x)=tan(x/2)xxsec^2(x/2)

Hence f'(g(x))=tan(g(x)/2)xxsec^2(g(x)/2)

and as g(x)=sqrt(5x-1)

f'(g(x))=tan(sqrt(5x-1)/2)xxsec^2(sqrt(5x-1)/2)