Where to find it:

NodeGraph / Right Mouse Click / Add Nodes / Math / Extension Pack / A /

return the arc hyperbolic cosine of the parameter

acosh returns the arc hyperbolic cosine of x; the non-negative inverse of cosh. The result is undefined if x<1

https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/acosh.xhtml

•X

Specify the value whose arc hyperbolic cosine to return.

•Output RGB

Separate computation for Input Channels Red, Green, Blue with an Alpha Channel of 1.0

•R

Computation for Input Red channel only, saved into R, G and B channel with an Alpha of 1.0

•G

Computation for Input Green channel only, saved into R, G and B channel with an Alpha of 1.0

•B

Computation for Input Blue channel only, saved into R, G and B channel with an Alpha of 1.0

•A

Computation for Input Alpha channel only, saved into R, G and B channel with an Alpha of 1.0