Arccos of −4/5
Arcsin, Arccos, Arctan, Arccot
What is arccos(−4/5)?
Answer
arccos(−4/5) ≈
143.1301° ≈ 2.4981 rad
Range: arccos x is an angle from 0° to 180°, so the answer is unique.
≈ — the value is not a table one; rounded to 4 decimal places.
−4/5 = −0.8.
arccos(−4/5) is the angle α in [0°, 180°] with cos α = −4/5.
arccos(−4/5) = 180° − arccos(4/5) ≈ 180° − 36.8699° = 143.1301°
cos 143.1301° ≈ −0.8000
α = arccos(−4/5) ≈ 143.1301°
P = (−0.8, 0.6)
P lies on the line x = −4/5 in the upper half of the circle, where sin α ≥ 0; highlighted: cos α = −4/5.
| Function | Degrees | Radians |
|---|---|---|
| arcsin(−4/5) | ≈ −53.1301° | ≈ −0.9273 |
| arccos(−4/5) | ≈ 143.1301° | ≈ 2.4981 |
| arctan(−4/5) | ≈ −38.6598° | ≈ −0.6747 |
| arccot(−4/5) | ≈ 128.6598° | ≈ 2.2455 |
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See Also
- Sin, Cos, Tan, Cot of an Angle - Exact value in square roots and the decimal, with reduction to an acute angle on the unit circle
- Square Root Calculator - Calculate the square root of any number
- Simplify Square Root Calculator - Write any square root in simplest radical form, step by step
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<a href="https://calculat.io/en/number/inverse-trigonometry/arccos---4-5">Arccos of −4/5 (Inverse Cosine) in Degrees and Radians</a>Facebook
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![Arccos of −4/5 (Inverse Cosine) in Degrees and Radians. arccos(−4/5) ≈ 143.1301° ≈ 2.4981 rad: the angle in [0°, 180°] whose cosine is −4/5. With the check and the unit circle.](https://calculat.io/en/number/inverse-trigonometry/arccos---4-5/generated.jpg)
Arccosine of nearby values
| x | arccos x |
|---|---|
| −1 | 180° = π |
| −√3/2 | 150° = 5π/6 |
| −4/5 | ≈ 143.1301° |
| −√2/2 | 135° = 3π/4 |
| −1/2 | 120° = 2π/3 |
| −0.3 | ≈ 107.4576° |
| 0 | 90° = π/2 |