Question

please help 4tan(2arctan1/3) solve

Answer 1

Two things to keep in mind....
First:
\[\Large \tan(2\theta) = \frac{2\tan(\theta)}{1- \tan^2(\theta)}\]

Second:
\[\Large \tan(\arctan x )=x\]

Answer 2

then?

Answer 3

Then?
Expand \(\large \tan(2\arctan \frac13)\)
using \[\Large \tan(2\theta) = \frac{2\tan(\theta)}{1- \tan^2(\theta)}\]
And taking \(\large \theta = \arctan\frac13\)