Trigonometry
Advanced

Tangent of a Difference

Angle subtraction formula for tangent.

Formula

tan⁡(A−B)=tan⁡A−tan⁡B1+tan⁡Atan⁡B\tan(A-B) = \frac{\tan A - \tan B}{1 + \tan A\tan B}

Variables

A,BAngles

Did You Know?

Setting the tangent difference to zero reveals when two lines are parallel — their angle difference vanishes.

subtractionidentity