Resultant Magnitude (law of cosines) (|R| = √(A² + B² + 2AB cos θ))
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|R| = √(A² + B² + 2AB cos θ)
What each symbol means
| Symbol | What it stands for |
|---|---|
| A | Magnitude of first vector |
| B | Magnitude of second |
| θ | Angle between directions of A and B when placed tail-to-tail |
| |R| | Magnitude of resultant |
When to use this
Planar vectors; θ measured between directions when tails coincide.