1. The problem statement, all variables and given/known data Differentiate with respect to the variable y=cos^-1((x/4) 2. Relevant equations cos^-1 x/a inverse cosine function -1/root a^2-x^2 3. The attempt at a solution Differentiated dy/dx=(1/root4^2-x^2)/3 Brought in the 3 for dy/dx=0.3x(1/root4^2-x^2) at this point i cant really see how to simplify this further. Can it be done. are the current steps correct?