differentiation help... chain rule?

George

New member
hi im currently stuck on a problem

df/dx=3x^2+2xy df/dy=x^2+2y+2 x(t)=sqrt 1+t^2 y(t)=-t dx/dt=t/sqrt 1+t^2 dy/dt= -1

now i have to use the chain rule df/dt=df/dx x dx/dt + df/dy x dy/dt

df/dt=(3x^2+2xy)(t/sqrt 1+t^2)+(x^2+2y+2)(-1)

Now substitute x = sqrt(1 + t^2), y = -t into df/dt

have i done all this correct so far , and can any one show me step by step how to finish it all , thanks.
 
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