# How do you call the relation between these 2 variables?

Let's say I have an X number and I want to increment it by 50%, I would get

$X*A=Y$

Then in order to multiply Y and get X again I would need to do

$Y*Z=X$

How do you call the relation between A and Z?

Example with numbers:

$$5*1.5=7.5$$ $$7.5*Z=5$$ $$Z=0.66$$

How do you call the relation between 1.5 and 0.66 when $X*1.5*0.66=X$?

## migrated from engineering.stackexchange.comFeb 26 '16 at 12:53

This question came from our site for professionals and students of engineering.

• @Fraaaan: There are many kinds of inverses: matrix inverse, trigonometric inverse (for example arcsine is the trigonometric inverse of sine but is not defined as 1/sine) etc. But generally reciprocal refers to multiplicative inverse. However, note that in some fields like engineering and physics there could also be many different concepts that have the name reciprocal – slebetman Feb 26 '16 at 4:39