Evaluate the following definite integral:
∫ (xe^(-x^2))dx
Note: ∫(a=0, b=1)
Any and all help is much appreciated! Thanks so much in advance!
∫ (xe^(-x^2))dx
Note: ∫(a=0, b=1)
Any and all help is much appreciated! Thanks so much in advance!
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∫ (xe^(-x^2))dx from 0 to 1
let x^2 = t, when x = 0, t = 0 and when x = 1, t = 1
2x dx = dt
x dx = dt/2
= 1/2∫ e^(-t))dt
= -(1/2)e^(-t) from [ 0 to 1]
= -1/2[1/e - 1 ]
= 1/2[1 - 1/e]
= 0.316
let x^2 = t, when x = 0, t = 0 and when x = 1, t = 1
2x dx = dt
x dx = dt/2
= 1/2∫ e^(-t))dt
= -(1/2)e^(-t) from [ 0 to 1]
= -1/2[1/e - 1 ]
= 1/2[1 - 1/e]
= 0.316
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w = -x²
dw ⁄ dx = -2x
- dw ⁄ 2 = x • dx
b
∫ x • e^(-x²) • dx = (-½) • ∫ eʷ • dw = (-½) • eʷ + C
a
= (-½) • e^(-x²) + C eval [a→b]
= (-½) • [ e^(-b²) − -e^(-a²) ]
= - [ e^(-b²) + e^(-a²) ] ⁄ 2
dw ⁄ dx = -2x
- dw ⁄ 2 = x • dx
b
∫ x • e^(-x²) • dx = (-½) • ∫ eʷ • dw = (-½) • eʷ + C
a
= (-½) • e^(-x²) + C eval [a→b]
= (-½) • [ e^(-b²) − -e^(-a²) ]
= - [ e^(-b²) + e^(-a²) ] ⁄ 2