MathCastle
TrigonometrySuperchallengeInverse Trigonometric Functions

Inverse Trigonometric Functions · Superchallenge problem

How many triples of positive integers (x,y,z)(x,y,z) with x≤y≤zx\le y\le z satisfy arctan⁡1x+arctan⁡1y+arctan⁡1z=π4\arctan\dfrac{1}{x}+\arctan\dfrac{1}{y}+\arctan\dfrac{1}{z}=\dfrac{\pi}{4}?