2Arctan(1/3) + arctan(1/7) = π/4(adsbygoogle = window.adsbygoogle || []).push({});

I try to solve it like this:

= sin(2arctan(1/3)) + sin(arctan(1/7) = sin(π/4)

But this isn't correct

What have I done wrong?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Exercise arctan

**Physics Forums | Science Articles, Homework Help, Discussion**