Arccos of 2/5
Arcsin, Arccos, Arctan, Arccot
What is arccos(2/5)?
Answer
arccos(2/5) ≈
66.4218° ≈ 1.1593 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.
2/5 = 0.4.
arccos(2/5) is the angle α in [0°, 180°] with cos α = 2/5.
cos 66.4218° ≈ 0.4000
α = arccos(2/5) ≈ 66.4218°
P ≈ (0.4, 0.9165)
P lies on the line x = 2/5 in the upper half of the circle, where sin α ≥ 0; highlighted: cos α = 2/5.
| Function | Degrees | Radians |
|---|---|---|
| arcsin(2/5) | ≈ 23.5782° | ≈ 0.4115 |
| arccos(2/5) | ≈ 66.4218° | ≈ 1.1593 |
| arctan(2/5) | ≈ 21.8014° | ≈ 0.3805 |
| arccot(2/5) | ≈ 68.1986° | ≈ 1.1903 |
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
Arccosine of nearby values
| x | arccos x |
|---|---|
| 1/4 | ≈ 75.5225° |
| 0.3 | ≈ 72.5424° |
| 1/3 | ≈ 70.5288° |
| 2/5 | ≈ 66.4218° |
| 1/2 | 60° = π/3 |
| 0.55 | ≈ 56.6330° |
| 4/7 | ≈ 55.1501° |
FAQ
What is arccos(2/5)?
arccos(2/5) ≈ 66.4218° ≈ 1.1593 rad
How to convert arccos(2/5) to radians?
Multiply the angle in degrees by π/180: 66.4218° × π/180 ≈ 1.1593 rad.
Why does a calculator show 1.1593 for arccos(2/5)?
The calculator is in radian mode (RAD) and gives the angle in radians: arccos(2/5) ≈ 1.1593 rad. In degrees (DEG) it is ≈ 66.4218°.
See Also
- Arccos of 0.14 (Inverse Cosine) in Degrees and Radians
- Arccos of 0.55 (Inverse Cosine) in Degrees and Radians
- Arccos of 0.65 (Inverse Cosine) in Degrees and Radians
- Arccos of 1 (Inverse Cosine) in Degrees and Radians
- Arccos of 1/2 (Inverse Cosine) in Degrees and Radians
- Arccos of 1/3 (Inverse Cosine) in Degrees and Radians
- Arccos of 1/4 (Inverse Cosine) in Degrees and Radians
- Arccos of 1/5 (Inverse Cosine) in Degrees and Radians
- Arccos of 2 (Inverse Cosine) in Degrees and Radians
- Arccos of 2/3 (Inverse Cosine) in Degrees and Radians
- Arccos of 3/4 (Inverse Cosine) in Degrees and Radians
- Arccos of 3/5 (Inverse Cosine) in Degrees and Radians
- Arccos of 4/5 (Inverse Cosine) in Degrees and Radians
- Arccos of 4/7 (Inverse Cosine) in Degrees and Radians
- Arccos of 12/13 (Inverse Cosine) in Degrees and Radians
- Arccos of 60 (Inverse Cosine) in Degrees and Radians
- Arccos of √2/2 (Inverse Cosine) in Degrees and Radians
- Arccos of √3/2 (Inverse Cosine) in Degrees and Radians
- Arccos of √3/3 (Inverse Cosine) in Degrees and Radians
- Arccot of −1 (Inverse Cotangent) in Degrees and Radians
- Арккосинус 2/5 (arccos 2/5) в градусах и радианах
- Arcocoseno de 2/5 (arccos 2/5) en grados y radianes
- Arco cosseno de 2/5 (arccos 2/5) em graus e radianos