Integrate the function: \(xsin\ 3x\)
Solution and Explanation
\(Let\ I=∫xsin\ 3xdx\)
Taking x as first function and \(sin\ 3x\) as second function and integrating by parts, we obtain
\(I= x∫sin\ 3x dx-∫{(\frac {d}{dx}x)∫sin\ 3x dx}\)
\(I = x(\frac {-cos\ 3x}{3})-∫1.(\frac {-cos\ 3x}{3})dx\)
\(I = \frac {-xcos\ 3x}{3}+\frac 13∫cos\ 3x dx\)
\(I = \frac {-xcos \ 3x}{3}+\frac 19sin\ 3x+C\)
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Concepts Used:
Integration by Partial Fractions
The number of formulas used to decompose the given improper rational functions is given below. By using the given expressions, we can quickly write the integrand as a sum of proper rational functions.
For examples,
