Need someone with a bigger brain than mine!

[Steve Martino]

Hello forum.  Trying to modify a formula to solve for a different variable.  Consider this formula which I am using and works fine:

x*(y/100)^.5

Here are the fields in the database.
Round(PUMPPRESSURE::gNozzSize*(PUMPPRESSURE::gOldPress/100)^.5;2)

In this case when 
x=.75 
y=145
The answer is rounded to .90  Works fine.

The first part of my question is this...
What I am trying to figure out is a formula that uses the previous result of .90, and if I change x to .65 get the new formula to provide an answer that calculates for y.  

With the above numbers, when I change x to .65 in this new calculation, solving for y should equal 190.  I can back into it with the first formula by consistently changing y until I get the .90 answer.

Just looking to automate it.

I'm usually pretty good with this but can't wrap my head around it.  The exponent .5,  is making my head hurt, LOL.
Thanks

Steve
 

Edited November 11, 2021 by Steve Martino

[comment]

I am not sure I understand the question. Let's say the formula is: 

z = x * ( y / 100)^.5

so that when the input is:
x = .75 ;
y = 145

then the output will be:

z = .9031195934094222

Are you asking how to calculate the value of y from the input of x and z? If so, the answer will be:

y = 100 * ( z / x )^2

 

Edited November 12, 2021 by comment

[Steve Martino]

You understood it perfectly.  That is correct.  Thanks!

[comment]

Ah, good. Just for future reference: 

n^.5 is the same thing as Sqrt(n) .  So the inverse of y = x^.5 is x = y^2.

 

[Steve Martino]

Thanks.  I last had calculus (and had any reason to use it!) in high school, in 1983, so much lost and forgotten.  Thanks again.