I'm having trouble coming up with an equation to graph this. I'm trying to create a visual representation of a product for an Excel graph or a calculator but can't figure out how to go about it.

This example (although poorly drawn) is similar to what I'm looking for. The values in this would be:
X= 30
Y= 700,000
Z= 31

The reason for having 3 variables is Z is where I need the curve to start, Y is the max value for the curve and X is how long the curve will last until coming back down to the original value. Another variable I didn't think of was I need it to be able to start at a value of 50,000 and not 0.

I'm not even sure where to start... any help would be appreciated. Thanks!

2. Originally Posted by MatthewJGale

I'm having trouble coming up with an equation to graph this. I'm trying to create a visual representation of a product for an Excel graph or a calculator but can't figure out how to go about it.

This example (although poorly drawn) is similar to what I'm looking for. The values in this would be:
X= 30
Y= 700,000
Z= 31

The reason for having 3 variables is Z is where I need the curve to start, Y is the max value for the curve and X is how long the curve will last until coming back down to the original value. Another variable I didn't think of was I need it to be able to start at a value of 50,000 and not 0.

I'm not even sure where to start... any help would be appreciated. Thanks!
One possibility could be to define the function piecewise:

$f(x)=\left\{\begin{array}{lcr}50 & , & x<31 \\-\frac{26}9 (x-46)^2+700 &, & 31 \leq x <61 \\ 50 &, & x \geq 61\end{array} \right.$

I've attached the graph of f. Note that the axes have different scales!

3. This is very helpful and a good direction to start.

Does anyone know how this would be used to graph in excel?