Asked by KKK

How does 0-(1/81)-((te^9t)/81)+(9e^9t/81)=(-1/81)-0+0? Where does the 0 come from?
Answered by oobleck
Hmmm. Some context would be nice.
if t=0 then ((te^9t)/81) = 0
But (9e^(9t)/81) = (9*1)/81 = 1/9