Question
Sun August 12, 2012 By:
 

Find dy/dx, x=e^t, y=5t^2.e^t, at t=-1

Expert Reply
Sun August 12, 2012
We have:
dx/dt = et
dy/dt = (5t2) (et) + (10t) (et) = (et) (5t2 + 10t)
 
Therefore,
dy/dx = (dy/dt) / (dx/dt) 
         = (et) (5t2 + 10t) / et
         = 5t2 + 10t
At t = -1,
dy/dx = 5 - 10 = -5
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