Geometry & Trigonometry
Intermediate

Tangent Identity

Defines tangent in terms of sine and cosine.

Formula

tan⁡θ=sin⁡θcos⁡θ\tan\theta = \frac{\sin\theta}{\cos\theta}

Variables

\thetaAngle

Example

tan 45° = sin45°/cos45° = (√2/2)/(√2/2) = 1.

Did You Know?

Tangent is sine over cosine — which is why it blows up to infinity wherever cosine hits zero.

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