Solving exponential

**DRFLETT** · 07-30-2010, 09:01 AM

The data below represent x and y values which fit an exponential equation

is there a way to use the solver to establish what x is when y is zero?

I need to do this for thousands of data sets like these so it needs to be fairly painless!

The answer is about 480!

140 -60.5342
200 -47.0959
300 -27.4384
400 -10.3562
500 4.82192
600 17
700 28.1781
800 38.1644
900 46.9315
1000 54.274
1100 61.2877
1200 66.6301

Thanks in advance

**pike** · 07-30-2010, 09:14 AM

Hi DRFLETT
if you click on the trend line you can show the equation for the data

**DRFLETT** · 07-30-2010, 09:29 AM

That is the way i do it now, but the problem is with thousands of these data sets, i would have to make individual graphs, get the equation, then solve it all manually.

I was hoping that it might be possible with LOGEST function or an array. The logest returns an error - i think because some of the values are negative.

Thanks though.

**shg** · 07-30-2010, 01:13 PM

See attached.

**Mads1032** · 11-17-2011, 12:36 AM

Hola,
So I have two y values and five x values, and I know what (x1,y1) and (x5,y5) are, and I know that I want the line between the two points to be an exponential growth line. I've graphed the two points on a scatter plot and then added the exponential line and got the equation for it. However, I want to change the slope of the graph to various steepness levels, and then be able to know what the inputs were.

Is there a way to come up with different scenarios by changing one input in the equation?

I attached what I'm looking at, and I only need the y values for the five single x values.

Let me know if this doesn't make sense...thanks for your help!