Using derivatives
for the function where mgu is a constant and if u = 0.2
critical points occur where the derivative is zero or undefined.
so first find your derivative, then you can see where it is undefined. that will be a critical point. then set it equal to zero and solve for , to find the other critical points (what is your dependent variable?)
to start you off, write as .
now use the chain rule (remember how to deal with constants)