The ACOSH function in Excel is used to calculate the inverse hyperbolic cosine of a given number. It is particularly useful in trigonometry and calculus to find the value of the hyperbolic angle whose cosine is equal to the specified number.

## Syntax

**ACOSH(number)**

## Arguments

number | The real number for which you want to find the inverse hyperbolic cosine. |

## How to use

The ACOSH function is quite straightforward to use. You provide a real number as the argument, and it returns the inverse hyperbolic cosine of that number. Here’s an example:

1 |
=ACOSH(2) |

This formula will return the value of the inverse hyperbolic cosine of 2, which is approximately 1.31696.

It’s important to note that the input number should be greater than or equal to 1 because the hyperbolic cosine function is only defined for values greater than or equal to 1. If you try to use ACOSH with a number less than 1, it will result in an error.

Let’s look at a few more examples:

1 |
=ACOSH(1) |

This formula will return 0 because the inverse hyperbolic cosine of 1 is 0.

1 |
=ACOSH(5) |

This formula will return approximately 2.29243 because the inverse hyperbolic cosine of 5 is around 2.29243.

## Additional information

The ACOSH function is part of Excel’s arsenal of trigonometric and mathematical functions. It’s particularly useful when dealing with hyperbolic trigonometry or solving mathematical problems involving the inverse hyperbolic cosine. Just remember to provide a valid argument, greater than or equal to 1, to get accurate results.