- #1

- 98

- 1

## Homework Statement

I have to find the deriv

of ##f(x)=xArctan(x^{3})##

I just need an explanation of how the arctan works...

So I understand the rest, but just the deriv of arctan itself is confusing for me.

So the derivative of ##arctan(x)## just in general is ##\frac{1}{1+x^{2}}##

But if it's of ##arctan(x^{3})##

Then I'm not sure what is right

So on my test I was pretty sure that when I derived arctan, that the x^2 factor meant (x)^2, so I would have to put in ##x^3##, and then I'd get ##\frac{1}{1+x^{6}}##

(That's x to the 6th, because you'd mult the exps)

But.... my test says I forgot to chain rule the ##x^{3}## that's inside of arctan(), but why did the teacher write (.3x^2) as the ##g'(x)##?

But I also wrote ##\frac{1}{1+3x^{4}}##, which wasn't marked wrong as the deriv of ##arctan(x^{3})##, so.. I'm confused.