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.