There will be instances where you will not see the curve appear in the graphing window. It is because its range is beyond the scale of the axes.
Here is an example:
The inverse function k/x is not visible in the graphing area.
When you cannot see the function, you can do the following to bring it in view:
Click on the '-' sign to zoom out. You should be able to see the curve now. In a few cases, you may need to zoom out more to see the curve.
You can use the position of the curve to decide how you can translate it and bring it closer to the actual data points.
In this case, we see that the inverse function needs to be stretched vertically. Increasing the parameter k stretches the function and gets it in the viewing window.
Once you have located the curve, click on the ‘+’ sign to revert to normal view.
Continue tweaking the parameter value until you get the best fit. For assistance with tweaking the parameter, please reference this article.
Once you are happy with the fit, you are all set to making sense of your function in the context of the data!