$\displaystyle \int e^x cosx dx$ Can someone walk me through this integral?
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Do you know integration by parts? If so do this twice.
After integrating twice I get: $\displaystyle e^x sinx + e^x cosx - \int cosx e^x$ Then what do I do?
Originally Posted by penguinpwn After integrating twice I get: $\displaystyle e^x sinx + e^x cosx - \int cosx e^x$ Then what do I do? $\displaystyle \int e^x \cos{x} \, dx = e^x \sin{x} + e^x \cos{x} - \int \cos{x} \cdot e^x \, dx$ $\displaystyle 2\int e^x \cos{x} \, dx = e^x \sin{x} + e^x \cos{x} + C$ finish up
Woah, did not know that trick. Thanks a ton!
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