Quick question - how to find intersection of y= e^(-x) and y= kx (1 Viewer)

[blackops23]

For one step of a certain question, I have to find:

for what value of k, does y=kx become tangent to y=e^(-x)

How do I go about doing this?

Thanks guys

 

[cutemouse]

k=-1

 

[jyu]

gradient = k =-e^(-x)
same y-coord =kx = e^(-x)
.: -k = kx, x = -1, k = -e

 

[cutemouse]

Woops. Serves me right for doing it in my head...