Cos(180°) = -1
Cosine — the x-coordinate of the corresponding unit-circle point, or adjacent/hypotenuse in a right triangle.
How to derive cos(180°)
At 180° the unit-circle point is (−1, 0). Cosine = x-coordinate = −1 — the minimum value cosine ever takes.
Unit-circle context
The angle 180° corresponds to π radians and sits on an axis on the unit circle.
Other trig values at 180°
Related cos values
Frequently asked
- What is the exact value of cos(180°)?
- The exact value is -1. Its decimal approximation is -1.
- How do you derive cos(180°)?
- At 180° the unit-circle point is (−1, 0). Cosine = x-coordinate = −1 — the minimum value cosine ever takes.
- What is 180° in radians?
- 180° equals π radians (multiply degrees by π/180).
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