Integral of e^(-x)*sin(x) dx
The solution
Detail solution
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Use integration by parts, noting that the integrand eventually repeats itself.
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For the integrand e−xsin(x):
Let u(x)=sin(x) and let dv(x)=e−x.
Then ∫e−xsin(x)dx=−∫(−e−xcos(x))dx−e−xsin(x).
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For the integrand −e−xcos(x):
Let u(x)=−cos(x) and let dv(x)=e−x.
Then ∫e−xsin(x)dx=∫(−e−xsin(x))dx−e−xsin(x)−e−xcos(x).
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Notice that the integrand has repeated itself, so move it to one side:
2∫e−xsin(x)dx=−e−xsin(x)−e−xcos(x)
Therefore,
∫e−xsin(x)dx=−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
/
2e−x(−sinx−cosx)
The graph
-1 -1
1 cos(1)*e e *sin(1)
- - ---------- - ----------
2 2 2
21−2e−1(sin1+cos1)
=
-1 -1
1 cos(1)*e e *sin(1)
- - ---------- - ----------
2 2 2
−2esin(1)−2ecos(1)+21
Use the examples entering the upper and lower limits of integration.