cos(150°) = -0.8660254, exactly −√3/2.
cos(150°) = -0.8660254, exactly −√3/2. The angle 150° equals 5π/6 radians (150 × π/180).
Exact form: −√3/2. Decimal: -0.8660254 (rounded to 8 places).
150° lies quadrant II. Remember that cosine is positive in quadrants I and IV, and negative in the others, which decides the sign of the answer.
If you get a different number, the calculator is probably in RAD mode. In radians you would enter 5π/6 instead of 150.
| sin 150° | = 0.5 |
| cos 150° | = -0.8660254 |
| tan 150° | = -0.57735027 |
| Angle | Radians | Cos |
|---|---|---|
| 0° | 0 | 1 |
| 30° | π/6 | 0.866025 |
| 45° | π/4 | 0.707107 |
| 60° | π/3 | 0.5 |
| 90° | π/2 | 0 |
| 120° | 2π/3 | -0.5 |
| 135° | 3π/4 | -0.707107 |
| 150° | 5π/6 | -0.866025 |
| 180° | π | -1 |
| 270° | 3π/2 | 0 |
| 360° | 2π | 1 |
cos(150°) = -0.8660254, exactly −√3/2.
150° = 5π/6 radians, so cos(150°) = cos(5π/6) = -0.8660254.
It is most likely set to radians. Switch to degree (DEG) mode before entering the angle.
Negative.
Yes. Use the calculator on this page, or open the full free Scientific Calculator with memory, history and keyboard support.