Integrate x^3*e^(-2x) dx
2007-07-31 05:42:59 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
I dont want the answer as much as help on how to do it...
2007-07-31 06:14:29 · update #1
Let u = -2x
Then use:
integral u^n e^u du = u^ne^u -n integral u^(n-1) e^u du
At the end use integral u e^u = e^u(u-1) +C
Just remember if u = -2x then dx = -du/2 and x^3 = -u^3/8
After making the substitutions, you have:
1/16 integral u^3e^u du and you are ready to use the above regression formula.
2007-07-31 06:13:15 · answer #1 · answered by ironduke8159 7 · 0⤊ 0⤋
If you are old enough to be learning calc you are too old to be cheating on your homework.
2007-07-31 12:44:58 · answer #2 · answered by snoopy 5 · 1⤊ 2⤋
ok this should be the answer, just not simplified:
(-2)(3e^(-2x))(x^(3e^(-2x-1))) (3e^(-2x))
2007-07-31 12:55:55 · answer #3 · answered by Brad A 2 · 1⤊ 0⤋