How do you differentiate f(x) = sqrt((5x+1)^2+(2x-1)) using the chain rule?

1 Answer
Nov 11, 2015

f'(x)=frac{25x+6}{sqrt(25x^2+12x)}

Explanation:

After simplifying,

f(x)=sqrt(25x^2+12x).

Let u=25x^2+12x.

Then, frac{du}{dx}=50x+12.

Using the chain rule,

f'(x)=frac{d}{dx}(sqrt(25x^2+12x))

=frac{d}{dx}(sqrt(u))

=frac{d}{du}(sqrt(u))frac{du}{dx}

=frac{1}{2sqrt(u)}(50x+12)

=frac{25x+6}{sqrt(25x^2+12x)}.