How do you differentiate the following parametric equation: x(t)=-2te^t+4t, y(t)= -2t^2-3e^(t) x(t)=2tet+4t,y(t)=2t23et?

1 Answer
Jul 12, 2017

the first derivative, dy/dx = dy/dt/dx/dtdydx=dydt/dxdt for parametric equations
the reason this holds true could be seen by treating dy, dx, and dtdy,dx,anddt as differentials (which they are) and upon dividing, dtdt cancels out and you are left with dy/dxdydx

as a refresher, d/dt(x^t) = tx^(t-1)ddt(xt)=txt1 and d/dt(e^t) = e^t * t'

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dy/dt = d/dt (-2t^2 - 3e^t) = -4t - 3e^t

dx/dt = d/dt (-2te^t + 4t) = -2(e^t + te^t) + 4

= -2e^t - 2te^t + 4

dy/dx = dy/dt/dx/dt = (-4t - 3e^t)/(-2e^t - 2te^t + 4)