## anonymous 5 years ago what the derivative of 2arctan(2x) ?

1. anonymous

$2( \frac{1}{1+4x^2})*2$

2. anonymous

4[1/(1+4x^2)]

3. anonymous

can you explain a little better how you got that?

4. anonymous

${d \over dx }\tan ^{-1}x=/1+x^2$

5. anonymous

apply this formula for 2arctan(2x)

6. anonymous

instead of x, here we have 2x, so by chain rule next we multiply with the derivative of 2x, that is 2

7. anonymous

8. anonymous

yes how did you get 4x^2?

9. anonymous

since instead of x,we have 2x.so (2x)^2=4x^2

10. anonymous

ok?

11. anonymous

ahhh gotcha...