(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The entire problem is in the attached picture. I have been checking and double checking for about an hour, found solutions online which agree with my solution, but I cannot find any answer beside -3.697 m/s which is marked wrong by the computer program.

2. Relevant equations

Is the homework program wrong or am I somehow missing something?

df/dt = (2x-y)/(2(x^2+y^2-xy)^(1/2))(dx/dt) + (2y-x)/(2*(x^2+y^2 -xy)^(1/2))(dy/dt)

3. The attempt at a solution

All of this works out to -3.697. I have tried rounding, leaving the answer as postive, nothing seems to work. Very frustrated.

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# Homework Help: Partial derivative problem... why is my answer wrong?

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