Show that the integral of e^(-kx)dx from 0 to 1 is 1/k(1-e^-k).

When I integrate from and calculate from 0 to 1, I get k(1-e^-k) instead of 1/k.

My solution is...

[-ke^(-kx)] upper limit 1, lower limit 0

= -ke^(-k) +k

= k(-e^(-k) +1)

Where did I go wrong?