## How to show 2arctan(1/2)=arctan(4/3)

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.

### How to show 2arctan(1/2)=arctan(4/3)

I've searched my whole trig book, looked through all my notes but still, I can't seem to figure this problem out! Can anyone give me some help? It would greatly be appreciated!

Show that: 2arctan(1/2)=arctan(4/3)
jinxt

Posts: 1
Joined: Wed Apr 22, 2009 12:36 am

### Re: How to show 2arctan(1/2)=arctan(4/3)

jinxt wrote:I've searched my whole trig book, looked through all my notes but still, I can't seem to figure this problem out! Can anyone give me some help? It would greatly be appreciated!

Show that: 2arctan(1/2)=arctan(4/3)

if you apply the tangent to both sides and use the formula...

$\tan(\alpha \pm \beta) = \frac{\tan( \alpha) \pm \tan (\beta)}{1 \mp \tan (\alpha) \tan( \beta)}$

Martingale

Posts: 363
Joined: Mon Mar 30, 2009 1:30 pm
Location: USA