 # Domain Restriction in Graphing Quadratic Regression

#1

I’m doing an activity on piecewise functions: Keeping Piece(wise) in the Family • Activity Builder by Desmos

I’m stuck on the last part. I want them to graph piecewise functions with non-linear equations. When they are doing linear functions, it’s easy to do a domain restriction on the point-slope equation. When it’s quadratic, I’ve found I need to use a regression equation, but I can’t put a domain restriction on a quadratic regression.

Is there a better way to write this so that they drag three points to create the quadratic function and the curve is only graphed between those points?

Thanks!

#2

So I think you can put a domain restriction on the regression. The parameters are saved as variables in the calculator, so just turn off the regression graph and make a new equation in standard form. See if this helps:

https://www.desmos.com/calculator/mf7ywhy7wy

#3

Thank you! That’s pretty much the only iteration I didn’t try.