How to prove that α+β=π/4 ? When α=arctan(1/2) and β=arctan(1/3) ?

1 Answer
Mar 26, 2018

Recall that

#tan(alpha + beta) = (tan alpha + tan beta)/(1 - tanalphatanbeta)#

We know that #tanalpha = 1/2# and #tanbeta = 1/3#. Therefore:

#tan(alpha + beta) = (1/2 + 1/3)/(1 - 1/2(1/3))#

#tan(alpha + beta) = (5/6)/(5/6)#

#tan(alpha + beta) = 1#

#alpha+ beta= arctan(1)#

#alpha + beta = pi/4#

As required.

Hopefully this helps!