Someone help me

In the Brachistochrone question, determine the equation provided by the curve that will give the shortest time, starting with the following functional that gives the time and applying the Euler-Lagrange equation different from the book. T[z] = (29)-1/2 [1 + (dz/dx)?]1/2 S*"1 dx You have to multiply dz/ dx to write the remaining terms after simplification as derivatives of a function.