Find the maximum rate of change of the function f(x,y) = (3 y^5)/x at the point (1,2) First I took the gradient of f(x,y)=<-3y^5*x^-2,15y^4*x^-1> and took the pt <1/sqrt(5),2/sqrt(5)> Then <-3y^5*x^-2,15y^4*x^-1>*<1/sqrt(5),2/sqrt(5)> the answer i get is 171.73 I'm not sure where my error is