Integral of x^2*exp(x^2) dx
The solution
Detail solution
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=x2 and let dv(x)=ex2.
Then du(x)=2x.
To find v(x):
ErfRule(a=1, b=0, c=0, context=exp(x**2), symbol=x)
Now evaluate the sub-integral.
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The integral of a constant times a function is the constant times the integral of the function:
∫πxerfi(x)dx=π∫xerfi(x)dx
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Don't know the steps in finding this integral.
But the integral is
2x2erfi(x)−2πxex2+4erfi(x)
So, the result is: π(2x2erfi(x)−2πxex2+4erfi(x))
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Now simplify:
2xex2−4πerfi(x)
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Add the constant of integration:
2xex2−4πerfi(x)+constant
The answer is:
2xex2−4πerfi(x)+constant
The answer (Indefinite)
[src]
/
| / / 2\ \
| / 2\ | 2 \x / | ____ 2
| 2 \x / ____ |erfi(x) x *erfi(x) x*e | \/ pi *x *erfi(x)
| x *e dx = C - \/ pi *|------- + ---------- - --------| + -----------------
| | 4 2 ____| 2
/ \ 2*\/ pi /
∫x2ex2dx=C+2πx2erfi(x)−π(2x2erfi(x)−2πxex2+4erfi(x))
The graph
____
E \/ pi *erfi(1)
- - --------------
2 4
−4πerfi(1)+2e
=
____
E \/ pi *erfi(1)
- - --------------
2 4
−4πerfi(1)+2e
Use the examples entering the upper and lower limits of integration.