Help with writing MATLAB code - Consider the function $f(x) = x \cos(-x^2)$

Help with writing MATLAB code - Consider the function $f(x) = x \cos(-x^2)$

Would anyone be able to help me with this question?
Consider the function:
$f(x) = x \cos(-x^2)$
Write MATLAB functions f.m and fp.m for the function $f$ and its
derivative $f '$, respectively.