Integral of x*exp(3*x-5) dx
The solution
Detail solution
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There are multiple ways to do this integral.
Method #1
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Rewrite the integrand:
xe3x−5=e5xe3x
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The integral of a constant times a function is the constant times the integral of the function:
∫e5xe3xdx=e5∫xe3xdx
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=x and let dv(x)=e3x.
Then du(x)=1.
To find v(x):
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Let u=3x.
Then let du=3dx and substitute 3du:
∫3eudu
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The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: 3eu
Now substitute u back in:
3e3x
Now evaluate the sub-integral.
-
The integral of a constant times a function is the constant times the integral of the function:
∫3e3xdx=3∫e3xdx
-
Let u=3x.
Then let du=3dx and substitute 3du:
∫3eudu
-
The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: 3eu
Now substitute u back in:
3e3x
So, the result is: 9e3x
So, the result is: e53xe3x−9e3x
Method #2
-
Rewrite the integrand:
xe3x−5=e5xe3x
-
The integral of a constant times a function is the constant times the integral of the function:
∫e5xe3xdx=e5∫xe3xdx
-
Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=x and let dv(x)=e3x.
Then du(x)=1.
To find v(x):
-
Let u=3x.
Then let du=3dx and substitute 3du:
∫3eudu
-
The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: 3eu
Now substitute u back in:
3e3x
Now evaluate the sub-integral.
-
The integral of a constant times a function is the constant times the integral of the function:
∫3e3xdx=3∫e3xdx
-
Let u=3x.
Then let du=3dx and substitute 3du:
∫3eudu
-
The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: 3eu
Now substitute u back in:
3e3x
So, the result is: 9e3x
So, the result is: e53xe3x−9e3x
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Now simplify:
9(3x−1)e3x−5
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Add the constant of integration:
9(3x−1)e3x−5+constant
The answer is:
9(3x−1)e3x−5+constant
The answer (Indefinite)
[src]
/
| / 3*x 3*x\
| 3*x - 5 | e x*e | -5
| x*e dx = C + |- ---- + ------|*e
| \ 9 3 /
/
∫xe3x−5dx=C+e53xe3x−9e3x
The graph
-5 -2
e 2*e
--- + -----
9 9
9e51+9e22
=
-5 -2
e 2*e
--- + -----
9 9
9e51+9e22
Use the examples entering the upper and lower limits of integration.