sirhc1
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Homework Statement
\int_0^∞ x^2exp(-x/2) dx
Homework Equations
The Attempt at a Solution
Using u substitution:
u = x/2
du = 1/2 dx
\int_0^∞ 4u^2exp(-u) du*2
= 8 \Gamma(3)
= 8*3!
= 48
But the correct answer is 16 when I plug it in Wolfram's definite integral calculator. I don't see where's my mistake?
Thank you very much!