# How do you show that #arctan(1/2)+arctan(1/3)=pi/4#?

##### 2 Answers

Jun 5, 2015

Jun 5, 2015

Let

(Note that, since

#tan A# is positive, we can further conclude that# < A < pi/4# )

Let

(As above, since the tangent of

#B# is positive.)

We need to show that

Use the formula for

Conclude that