I'm supposed to find (assume all these d's are the partial derivative sign, not d)(adsbygoogle = window.adsbygoogle || []).push({});

d^2z/dxdy, d^2z/dx^2, and d^2z/dy^2

The one I can't do is z^2 + sinx = tany

I set it equal to zero, so z^2 + sinx - tany=0

so dz/dx = - Fx/Fz = sec^2y/2z

dz/dy = - Fy/Fz = -cosx/2z

multiply them for d^2z/dxdy I get -(sec^2y*cosx)/(4z^2) which is ALMOST right, but the book says the denominator is 4z^3, and the other two I do the same procedure(dz/dx * dz/dx for the second one for example) and get nothing close

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# Help with this partial derivative problem

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