Справка LibreOffice 24.8

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

МНИМ.COSH(КомплексноеЧисло)

Complex_number is a complex number whose hyperbolic 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.

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.

=МНИМ.COSH("4-3i")

возвращает -27,0349456030742-3,85115333481178i.

=IMCOSH(2)

returns 3.76219569108363 as a string. The imaginary part is equal to zero, so it is not displayed in the result.