# How do you calculate the derivative of #intarctan t dt # from #[2,1/x]#?

##### 2 Answers

Aug 14, 2015

#### Explanation:

Aug 14, 2015

Use the Fundamental Theorem of Calculus, Part 1 and the chain rule.

#### Explanation:

Fundamental Theorem of Calculus, Part 1 tells us that if

then (

and (

**and #g'(x) = f(x)#** (which is what we need here).

In this problem we have a composition, so we need the chain rule:

So the chain rule gives us:

In this case:

# = - arctan(1/x)/x^2#