Integral of cos(x)*exp(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 excos(x):
Let u(x)=cos(x) and let dv(x)=ex.
Then ∫excos(x)dx=excos(x)−∫(−exsin(x))dx.
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For the integrand −exsin(x):
Let u(x)=−sin(x) and let dv(x)=ex.
Then ∫excos(x)dx=exsin(x)+excos(x)+∫(−excos(x))dx.
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Notice that the integrand has repeated itself, so move it to one side:
2∫excos(x)dx=exsin(x)+excos(x)
Therefore,
∫excos(x)dx=2exsin(x)+2excos(x)
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Now simplify:
22exsin(x+4π)
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Add the constant of integration:
22exsin(x+4π)+constant
The answer is:
22exsin(x+4π)+constant
The answer (Indefinite)
[src]
/
| x x
| x cos(x)*e e *sin(x)
| cos(x)*e dx = C + --------- + ---------
| 2 2
/
∫excos(x)dx=C+2exsin(x)+2excos(x)
The graph
1 E*cos(1) E*sin(1)
- - + -------- + --------
2 2 2
−21+2ecos(1)+2esin(1)
=
1 E*cos(1) E*sin(1)
- - + -------- + --------
2 2 2
−21+2ecos(1)+2esin(1)
-1/2 + E*cos(1)/2 + E*sin(1)/2
Use the examples entering the upper and lower limits of integration.