# #Div/0! error when solving for a single variable

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# #Div/0! error when solving for a single variable

I am trying to create a solver that will solve for Viscosity in this equation when I input variables for Velocity, mass, thickness, time, area, and gravity.

Here is my equation I am trying to create in excel:

V=[(m*g*h)/(mu*A)]*(1+(e^((-t*mu*A)/(h*m)))

Where V=Velocity, m = mass, g = gravity, A= Area, h = thickness, t=time, and mu = viscosity

I created this table for my given values, as you can see I do not have a value for Viscosity as I am trying to solve for that variable using goal seek, however I am thrown errors when trying to solve.

Any suggestions?

 Viscosity from Velocity Problem 7 Variable Value Velocity (m/s) 1 Mass(kg) 6 Area(m^2) 0.0025 Thickness(m) 0.0005 Time(s) 1 Gravity(m/s^2) 9.81 Viscosity #N/A

# Re: #Div/0! error when solving for a single variable

@rulerian9 Start by creating a formula in Excel that calculates

=[(m*g*h)/(mu*A)]*(1+(e^((-t*mu*A)/(h*m)))-V

referencing each part of the equation to the relevant cell in the table with the values.

Enter any number for 'mu'.

Now use Goal Seek (from the Tools menu on your Mac) and set the cell with the formula to zero by changing the cell that holds the number for mu.

In the attached example it would look like this.

Note that I broke up the formula into smaller pieces as I don't really know what I'm dealing with. I would get confused otherwise. And I don't even know if I got the formula right (physics is not my line of business, sorry!).

It demonstrates the Goal Seek feature. And you can do it for any of the other variables. So if you don't know m but everything else is known, set cell E12 to 0 by changing C5.