Use our online Arccos calculator and Inverse cosine calculator (cos-1 calculator).
If you want to convert the result to a different angel use our online angle converter.
Cos−1(x), Arccos Example
Example 1: find the exact value for cos[arccos (-0.5)]
If the cosine of 120° is -0.5 which give us cos (120°)=-0.5 then cos[arccos (-0.5)]=-0.5.
but we can avoid to perform all this calculation by simple using the properties of cos-1(arccos) since -1≤-0.5≤1 then cos[arccos (-0.5)]=-0.5.
Example 2: find the exact value for cos[arccos (2/3)]
we can just use the our arccos calculator which will gave us arccos(2/3) = 0.841068671 rad then cos (0.841068671)= 2/3
but we can avoid to perform all this calculation by simple using the properties of cos-1(arccos) we convert the since -1≤-2/3≤1 then cos[arccos (2/3)]=2/3.
Cos−1(x), Arccos Definition:
Definition of Arccos provided by wikipedia:
arccos (trigonometry), the inverse trigonometric function of cosine.
In mathematics, the inverse trigonometric functions (occasionally called cyclometric functions) are the inverse functions of the trigonometric functions (with suitably restricted domains). Specifically, they are the inverses of the sine, cosine, tangent, cotangent, secant, and cosecant functions, and are used to obtain an angle from any of the angle’s trigonometric ratios. Inverse trigonometric functions are widely used in engineering, navigation, physics, and geometry.
The arccosine of x is defined as the inverse trigonometric function of cosine when -1≤x≤1.
cos y = x.
Then the arccosine of x is equal to the inverse cosine trigonometric function of x, which is equal to y:
arccos x = cos-1 x = y.Cos−1(x), ArccosDefinition.
Arccos Table (cos-1) :
|Angle Units||(rad) terms of pi||(°) in degrees|