# How do you evaluate arctan(1/2)?

The arctan(1/2) è l'angolo theta così tan(theta) = 1/2

We can imagine such an angle in the first quadrant as being part of a right-triangle with opposite side =1, lato adiacente =2, and hypotenuse =sqrt(5).

Unfortunately this is not one of the standard angles and the only way (as far as I can tell) to evaluate it is to use a calculator (or something similar) to look-up:

arctan(1/2) = 0.463648 " radians" = 26.56505^@