What is the derivative of this function y=sec^-1(5x)?

1 Answer
May 5, 2018

(dy)/(dx)=1/(|x|sqrt(25x^2-1))

Explanation:

We know that,

color(red)(d/(dt)(sec^-1t)=1/(|t|sqrt(t^2-1))

Here,

y=sec^-1(5x)

Let.

y=sec^-1u ,where, u=5x

=>(dy)/(du)=1/(|u|sqrt(u^2-1)) and (du)/(dx)=5

"Using "color(blue)"Integration by Parts"

color(blue)((dy)/(dx)=(dy)/(du)*(du)/(dx)

So,(dy)/(dx)=1/(|u|sqrt(u^2-1))xx5
(dy)/(dx)=5/(|5x|sqrt(25x^2-1))

(dy)/(dx)=1/(|x|sqrt(25x^2-1))