What's the derivative of sqrt[arctan(x)]arctan(x)?

1 Answer
Nov 24, 2016

1/(2(x^2+1)sqrtarctan(x)12(x2+1)arctan(x)

Explanation:

This can be written as (arctan(x))^(1/2)(arctan(x))12.

This is in the form u^(1/2)u12. The chain rule with the power rule tells us that:

d/dxu^(1/2)=1/2u^(-1/2)*u'=1/(2sqrtu)*u'

So for arctan(x), whose derivative is 1/(x^2+1), this becomes

d/dxsqrtarctan(x)=1/(2sqrtarctan(x))*1/(x^2+1)