integrate

∫0∞xeaxdx(limits from 0 to ifinity)

9 Answers

4
UTTARA ·

Integrating By parts

I = x eax /a ]∞0 - eax/a2 ]∞0

1
Debanjana Mukher ·

ya but in dat case answer is cuming ∞.how is dat possible??

1
RAY ·

agar limits waisa hai toh answer toh waisa aayega!!

62
Lokesh Verma ·

see the integral will be inifinite simply becasue the function itself is gettting larger and larger with x...

If a is -ve then teh answer could be different.. (What do you think?? )

1
Debanjana Mukher ·

ya obviously a has to be negative.let a=-b(b>0).then we put limits -∞ to 0.but then wat about xe-bx/bdx at x=-∞??

62
Lokesh Verma ·

Then the sign will reverse.

and the role of the sign willl get reversed....

Are you talking about the limit or the integral?

1
Debanjana Mukher ·

i did it by integration by parts n then im putting ∞ in place of x but wat is da limiting value of -(xe-bx)/b at x=∞?

66
kaymant ·

As x→∞, if b > 0, then e-bx → 0 and since the exponential is much faster than any polynomial for large x, the quantity xe-bx → 0 as well. But this quantity grows without bound if b < 0.

1
Debanjana Mukher ·

ok i got it.thank u..

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