# Documentation/Calc Functions/IMCOS

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## Function name:

IMCOS

## Category:

Add-in

## Summary:

Returns the cosine of a complex number. The cosine of a complex number can be expressed by:

cos(a+bi) = cos(a)cosh(b) - sin(a)sinh(b)i

## Syntax:

IMCOS(**Complex_number**)

## Returns:

The result is presented in the string format and has the character "i" or "j" as an imaginary unit.

The function always returns a string representing a complex number. If the result is a complex number with one of its parts (a or b) equal to zero, that part is not displayed.

## Arguments:

**Complex_number** is a complex number whose cosine is to be calculated.

A complex number is a string expression resulting in the form "a+bi" or "a+bj", where a and b are numbers. If the complex number is actually a real number (b=0), then it can be either a string expression or a number value.

## Additional details:

## Examples:

=IMCOS("4-3i") returns -6.58066304055116-7.58155274274654i.

=IMCOS(2) returns -0.416146836547142 as a string. The imaginary part is equal to zero, so it is not displayed in the result.

## Related LibreOffice functions:

## ODF standard:

This function is part of the Open Document Format for Office Applications (OpenDocument) standard Version 1.2. (ISO/IEC 26300:2-2015)