# Inverse Cosine Calculator

Trigonometric inverse cosine calculator

Between -1 and 1

## #What is inverse cosine

Inverse cosine is the inverse of the basic cosine function. In the cosine function, the value of angle θ is taken to give the ratio adjacent/hypotenuse. However, the inverse cosine function takes the ratio adjacent/hypotenuse and gives angle θ.

## Inverse cosine symbol

Inverse cosine is represented as cos-1 or arccos.

## #Inverse cosine rule

The rule for inverse cosine is derived from the rule of the cosine function.

a2 = b2 + c2 - 2bc cos⁡(A)

Rearraning the equation to get cos-1 rule:

a2 - b2 - c2 = -2bc cos⁡(A)

a2 - b2 - c2 / 2bc = cos⁡(A)

cos-1 (a2 - b2 - c2 / 2bc)

## #Arccos table

Inverse cosine table
arccos(-1.0) 180.00 3.14
π
arccos(-0.9) 154.15 2.69
arccos(-0.8) 143.13 2.49
arccos(-0.7) 134.42 2.34
arccos(-0.6) 126.86 2.21
arccos(-0.5) 120.00 2.09
2π / 3
arccos(-0.4) 113.57 1.98
arccos(-0.3) 107.45 1.87
arccos(-0.2) 101.53 1.77
arccos(-0.1) 95.73 1.67
arccos(0.0) 90.00 1.57
π / 2
arccos(0.1) 84.26 1.47
arccos(0.2) 78.46 1.36
arccos(0.3) 72.54 1.26
arccos(0.4) 66.42 1.15
arccos(0.5) 60.00 1.04
π / 3
arccos(0.6) 53.13 0.92
arccos(0.7) 45.57 0.79
arccos(0.8) 36.86 0.64
arccos(0.9) 25.84 0.45
arccos(1.0) 0.00 0.00