Invalid variable definition

[나윤_10344731]

I definitely defined f(x,beta), but when I try to draw a diagram, the following error occurs.

How can I solve this problem?

Inside the red box, "This variable is not defined. Make sure the label is set correctly."

[VladimirN]

Please upload your Mathcad Prime worksheet here.

[나윤_10344731]

Here is my worksheet. thank you!

[ttokoro · Accepted solution]

Move your plot under the definition of RFfit(x).

[나윤_10344731]

Thank you so much..!!