# Understanding how to use implicitdiff command in Maple 17

I am given a system $$\left\{\begin{matrix}xy^2+zu+v^2=3 \\ x^3z+2y-uv=2 \\ xu+yv-xyz=1 \end{matrix}\right.$$ which defines x, y, z as functions of (u,v) around (1, 1, 1, 1, 1). I've been asked to compute $$\frac{\partial y}{\partial u}(1, 1)$$ and $$\frac{\partial z}{\partial v}(1, 1)$$

I've been struggling to understand how to use the implicitdiff command in Maple. I have looked on Maple Help but I am still confused about how to identify my parameters. If anyone can offer some clarification/tips, that would be greatly appreciated!

Let

eqs:= {x*y^2 + z*u + v^2=3,x^3*z+2*y-u*v=2,x*u + y*v - x*y*z = 1};


For $\partial y/\partial u$, you would use

implicitdiff(eqs, {x,y,z},y,u);


and then of course you can evaluate this at $(x,y,z,u,v) = (1,1,1,1,1)$:

eval(%, {x=1,y=1,z=1,u=1,v=1});

• Would the other implicit differentiation be: implicitdiff(eqs, {x, y, z}, z, v)? I've tried putting this in but it returns a 'fail'. I'm not sure what I've entered in wrong. – grizzly.bear Apr 7 '16 at 22:58
• For implicitdiff(eqs, {x, y, z}, z, v), I get $${\frac {-6\,{x}^{3}{z}^{2}v-6\,{y}^{2}{x}^{3}z+{y}^{2}xzu+6\,{x}^{2}z{ v}^{2}-2\,yx{u}^{2}+{y}^{2}uv+4\,yzv+2\,{y}^{3}-4\,uv}{-5\,{y}^{2}{x}^ {4}z-2\,y{x}^{4}u+3\,{x}^{3}{z}^{2}u+{y}^{2}{x}^{3}v-3\,{x}^{2}zuv+2\, {y}^{3}x-2\,yzu+2\,{u}^{2}}}$$ I don't know where your "fail" is coming from. Maybe a typo somewhere. – Robert Israel Apr 8 '16 at 15:51