Integral of e^(-x)sinx dx
The solution
Detail solution
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Let u=−x.
Then let du=−dx and substitute du:
∫eusin(u)du
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Use integration by parts, noting that the integrand eventually repeats itself.
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For the integrand eusin(u):
Let u(u)=sin(u) and let dv(u)=eu.
Then ∫eusin(u)du=eusin(u)−∫eucos(u)du.
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For the integrand eucos(u):
Let u(u)=cos(u) and let dv(u)=eu.
Then ∫eusin(u)du=eusin(u)−eucos(u)+∫(−eusin(u))du.
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Notice that the integrand has repeated itself, so move it to one side:
2∫eusin(u)du=eusin(u)−eucos(u)
Therefore,
∫eusin(u)du=2eusin(u)−2eucos(u)
Now substitute u back in:
−2e−xsin(x)−2e−xcos(x)
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Now simplify:
−22e−xsin(x+4π)
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Add the constant of integration:
−22e−xsin(x+4π)+constant
The answer is:
−22e−xsin(x+4π)+constant
The answer (Indefinite)
[src]
/
| -x -x
| -x cos(x)*e e *sin(x)
| E *sin(x) dx = C - ---------- - ----------
| 2 2
/
∫e−xsin(x)dx=C−2e−xsin(x)−2e−xcos(x)
The graph
-1 -1
1 cos(1)*e e *sin(1)
- - ---------- - ----------
2 2 2
−2esin(1)−2ecos(1)+21
=
-1 -1
1 cos(1)*e e *sin(1)
- - ---------- - ----------
2 2 2
−2esin(1)−2ecos(1)+21
1/2 - cos(1)*exp(-1)/2 - exp(-1)*sin(1)/2
Use the examples entering the upper and lower limits of integration.