I need to derive the expression for the gradient operator in spherical coordinates. I know the following R =sqrt(x^2+y^2+z^2) theta, call it %, = arctan sqrt(x^2+y^2)/z phi, arctan (y/x) Using dT/dx= dT/dR*dr/dx+dT/d%*d%/dx+dT/dphi*dphi/dx, do partial derivates... dR/dx = x/(sqrt(x^2+y^2+z^2) d%/dx = xz/[(sqrt(x^2+y^2)*(x^2+y^2+z^2)] dphi/dx = -y/sqrt(x^2+y^2) The place these values into the listed value dT/dx. so its, dT/dx = dT/dR*x/(sqrt(x^2+y^2+z^2)+ dT/d%*xz/[(sqrt(x^2+y^2)*(x^2+y^2+z^2)]+ dT/dphi*y/sqrt(x^2+y^2) From here I don't know what to do or even if I am doing it right. Its been a while since i have taken calc. I know there is some relations for the trig functions, but can't seems to find them. the final solution for del gradiant in spherical is R^*d/dr+theta^/r*d/dtheta+phi^/r sin (phi) *d/dphi. I'm really lost and need some help. Thanks in advance.