1. inverse trig functions

hey guys

how exactly do i prove inverse tan 4 - inverse tan 3/5 = pi/4

2. Originally Posted by xwrathbringerx
hey guys

how exactly do i prove inverse tan 4 - inverse tan 3/5 = pi/4
Let $\tan^{-1} 4 = \alpha$ and $\tan^{-1} \left(\frac{3}{5}\right) = \beta$.

Then your task is to show that $\alpha - \beta = \frac{\pi}{4}$, that is, $\tan(\alpha - \beta) = 1$ ....