# Arccosine

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## Definition Of Arccosine

Arccosine is the inverse function of cosine. It is also written as arccos or cos-1.
If y = cos x, then x = arccos y.

### Examples of Arccosine

or
This means that the angle 300 has cosine equal to .

### Solved Example Clockple on Approximate

#### Ques:

##### Choices:

A. 0.3
B. 0.2
C. 0.5
D. 0.6
Correct Answer: D

#### Solution:

Step 1: Recall that cos(arccos x) = x, for - 1 ≤ x ≤ 1.