Create a function called linefit based on the information in the background file. The function has the following properties:

Create a function called linefit based on the information in the background file. The function has the following properties: a. Inputs - X data points (nx1) column vector and Y data points (nx1) column vector. b. Outputs - Beta values (2x1) column vector and the design matrix D. c. Objective - Use the X data points to form the design matrix D for the first-degree polynomial estimation. Use this and the Y column vector to calculate the two beta parameter values.

my code keeps getting error when I create the function linefit. It says file 'linefit' not found.