MATH
posted by Anonymous .
what is the integration of e^x from negative infinity to x ?

since x = x for x < 0.
∫[∞,x] e^t dt
= ∫[∞,x] e^t dt if x < 0
= e^t
So, for x>=0,
∫[∞,x] e^t dt
= ∫[∞,0] e^t dt + ∫[0,x] e^t dt
= 1 + (1e^x)
= 2  e^x 
What if we have .. integration of xe^(x) dx from negative infinity to x.

No idea. Do it the way I did, but you have to use integration by parts. If you get stuck, show how far you got.
You should wind up with
(x+1)e^x for x<0
(x1)e^x for x>=0
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