# Find the value of: tan(100) + tan(125) + tan(100)•tan(125)

The question given was - solve all the equations that are possible to solve without a calculator. (This is a part of it) Please try to solve this question (obviously without a calculator) if it's possible. :) thanks in advance.

All values are in degrees

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We are mathematicians, how do you even know the value exists ;-) – dcs24 May 6 '14 at 11:24
Using calculator the answer is 1. I am not able to reach it. :| – Mercury May 6 '14 at 11:27
Hence, the answer is 1. – evil999man May 6 '14 at 11:27
(-1) for that, Awesome. – Mercury May 6 '14 at 11:28
Hint: What is $\tan 225^{\circ}$, and use the addition formula for tan. – Macavity May 6 '14 at 11:29

Hint: $\tan(\alpha + \beta)=\dfrac{\tan(\alpha)+\tan(\beta)}{1-\tan(\alpha)\tan(\beta)}$ and $\tan(225^\circ)=1$.