Arccos of 1/5
Arcsin, Arccos, Arctan, Arccot
What is arccos(1/5)?
Answer
arccos(1/5) ≈
78.4630° ≈ 1.3694 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.
1/5 = 0.2.
arccos(1/5) is the angle α in [0°, 180°] with cos α = 1/5.
cos 78.4630° ≈ 0.2000
α = arccos(1/5) ≈ 78.4630°
P ≈ (0.2, 0.9798)
P lies on the line x = 1/5 in the upper half of the circle, where sin α ≥ 0; highlighted: cos α = 1/5.
| Function | Degrees | Radians |
|---|---|---|
| arcsin(1/5) | ≈ 11.5370° | ≈ 0.2014 |
| arccos(1/5) | ≈ 78.4630° | ≈ 1.3694 |
| arctan(1/5) | ≈ 11.3099° | ≈ 0.1974 |
| arccot(1/5) | ≈ 78.6901° | ≈ 1.3734 |
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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--1-5">Arccos of 1/5 (Inverse Cosine) in Degrees and Radians</a>Facebook
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![Arccos of 1/5 (Inverse Cosine) in Degrees and Radians. arccos(1/5) ≈ 78.4630° ≈ 1.3694 rad: the angle in [0°, 180°] whose cosine is 1/5. With the check and the unit circle.](https://calculat.io/en/number/inverse-trigonometry/arccos--1-5/generated.jpg)
Arccosine of nearby values
| x | arccos x |
|---|---|
| 0 | 90° = π/2 |
| 0.1 | ≈ 84.2608° |
| 0.14 | ≈ 81.9522° |
| 1/5 | ≈ 78.4630° |
| 1/4 | ≈ 75.5225° |
| 0.3 | ≈ 72.5424° |
| 1/3 | ≈ 70.5288° |