law of tangents

: a law in plane trigonometry: in any plane triangle the tangent of one half the difference of any two angles is to the tangent of one half their sum as the difference of the sides opposite the respective angles is to the sum of those sides

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now