MathDB
CSMC 2018 Part A Problem 6

Source:

November 24, 2018
CSMCCSMC 2018

Problem Statement

Suppose that 0<A<900^\circ < A < 90^\circ and 0<B<900^\circ < B < 90^\circ and (4+tan2A)(5+tan2B)=320tanAtanB\left(4+\tan^2 A\right)\left(5+\tan^2 B\right) = \sqrt{320}\tan A\tan B Determine all possible values of cosAsinB\cos A\sin B.