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**ACOS(**//expression//**)**

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| **ACOS** | Returns inverse cosine. |
| //expression// | A numeric constant, variable, or expression for the value of the cosine. |

The **ACOS** procedure returns the inverse cosine. The inverse of a cosine is the angle that produces the cosine. The return value is the angle in radians. p is a constant which represents the ratio of the circumference and radius of a circle. There are 2p radians (or 360 degrees) in a circle.

| **Return Data Type:** | REAL |

**Example:**

**PI       EQUATE(3.1415926535898)     !The value of PI**

**Rad2Deg  EQUATE(57.295779513082)     !Number of degrees in a radian**

**Deg2Rad  EQUATE(0.0174532925199)     !Number of radians in a degree**

** CODE**

** InvCosine = ****ACOS****(CosineAngle)       !Get the Arccosine**

**See Also:**

[[tan  return tangent .htm|TAN]]

[[atan  return arctangent .htm|ATAN]]

[[sin  return sine .htm|SIN]]

[[asin  return arcsine .htm|ASIN]]

[[cos  return cosine .htm|COS]]