Using this inverse cosine (arccos) calculator, you can quickly calculate the inverse cosine function. The result is displayed in degree and radians.

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The inverse trigonometric functions are the inverse functions of trigonometric functions in mathematics. They are the inverses of the sine, cosine, tangent, cotangent, secant, and cosecant functions, respectively. They’re most commonly applied to calculate an angle from one of the angle’s trigonometric ratios.

The inverse of the cosine function is the ** arccos** function. It returns the angle with a given cosine.

For example,

If the cosine of 45° is 0.707106781:

cos(45°) = 0.707106781

Then the arccos of 0.707106781 is 45°:

arccos(0.707106781) = cos^{-1}(0.707106781) = 45°

**Arccos Calculator Use**

- This calculator is simple and quick to use.
- Simply enter the value as a real number, within the domain of arccos function in between -1 to 1.
- Once you’ve entered the value, the calculator will show you the results in degree and radians.

**Arccos Formula**

The formula to calculate the inverse of cosine is mentioned below:

**Evaluate : cos**^{-1} (0)

^{-1}(0)

you will need to find that angle θ in [0, *π*] for which cos θ = 0. It’s not hard to see that cos^{-1} (0) = *π* /2 . If you calculate this on your calculator and get 90, your calculator is in degrees mode. In this event, you should immediately change it to radians mode.

There is a simple formula for converting degrees to radians.

**Radian = Degree*( π / 180)**

So **90 degree** is equals to **1.5708 radians** [90*( *π* /180)]