Cos(150°) = -√3/2
Cosine — the x-coordinate of the corresponding unit-circle point, or adjacent/hypotenuse in a right triangle.
How to derive cos(150°)
150° is in quadrant II. Reference angle = 30°, cosine negative in Q2, so cos(150°) = −cos(30°) = −√3/2.
Unit-circle context
The angle 150° corresponds to 5π/6 radians and sits Quadrant II on the unit circle.
Its reference angle is 30°, which is why cos(150°) shares its absolute value with cos(30°).
Other trig values at 150°
Related cos values
Frequently asked
- What is the exact value of cos(150°)?
- The exact value is -√3/2. Its decimal approximation is -0.86603.
- How do you derive cos(150°)?
- 150° is in quadrant II. Reference angle = 30°, cosine negative in Q2, so cos(150°) = −cos(30°) = −√3/2.
- What is 150° in radians?
- 150° equals 5π/6 radians (multiply degrees by π/180).
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