1 / | | 5*x | e *cos(7*x) dx | / 0
Use integration by parts, noting that the integrand eventually repeats itself.
For the integrand :
Let and let .
Then .
For the integrand :
Let and let .
Then .
Notice that the integrand has repeated itself, so move it to one side:
Therefore,
Now simplify:
Add the constant of integration:
The answer is:
/ | 5*x 5*x | 5*x 5*cos(7*x)*e 7*e *sin(7*x) | e *cos(7*x) dx = C + --------------- + --------------- | 74 74 /
5 5 5 5*cos(7)*e 7*e *sin(7) - -- + ----------- + ----------- 74 74 74
=
5 5 5 5*cos(7)*e 7*e *sin(7) - -- + ----------- + ----------- 74 74 74
Use the examples entering the upper and lower limits of integration.