Question:medium

\[ \int \frac{x + 5}{(x + 6)^2} e^x \, dx \] is equal to:

Show Hint

When dealing with rational functions and exponential terms, try using substitution to simplify the integrand.
  • $\log(x + 6) + C$
  • $e^x + C$
  • $\frac{e^x}{x + 6} + C$
  • $-\frac{1}{(x + 6)^2} e^x + C$
Show Solution

The Correct Option is C

Solution and Explanation

The integral \( \int \frac{x + 5}{(x + 6)^2} e^x \, dx \) can be simplified using substitution. Let $u = x + 6$, implying $du = dx$ and $x = u - 6$. The integral transforms to \( \int \frac{(u - 6) + 5}{u^2} e^{u - 6} \, du \), which simplifies to \( \int \frac{u - 1}{u^2} e^{u - 6} \, du \). This can be decomposed into \( \int \frac{1}{u} e^{u - 6} \, du - \int \frac{1}{u^2} e^{u - 6} \, du \). The first term evaluates to $\frac{e^{u-6}}{u}$. The second term, requiring integration by parts or identification of a standard form, yields \( \frac{e^x}{x + 6} + C \).
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