MATLAB: Three element vector function

Question

Create a MATLAB function that, given a three element vector [x1 x2 x3] as input, calculates r = x1^2 + x2^2 − x3^2.

Answer 1

function r = myfunc(x)
r = x(:,1).^2 + x(:,2).^2 - x(:,3).^2 ;