evaluate the following integral.\n int\frac{dx}{x^{2}+2x + 37}

evaluate the following integral.\n int\frac{dx}{x^{2}+2x + 37}
Answer
Explanation:
Step1: Complete the square in the denominator
We have $x^{2}+2x + 37=(x + 1)^{2}+36$. So the integral becomes $\int\frac{dx}{(x + 1)^{2}+36}$.
Step2: Use substitution
Let $u=x + 1$, then $du=dx$. The integral is $\int\frac{du}{u^{2}+36}$.
Step3: Recall the integral formula
The formula for $\int\frac{du}{u^{2}+a^{2}}=\frac{1}{a}\arctan(\frac{u}{a})+C$. Here $a = 6$. So $\int\frac{du}{u^{2}+36}=\frac{1}{6}\arctan(\frac{u}{6})+C$.
Step4: Substitute back
Substitute $u=x + 1$ back into the result. We get $\frac{1}{6}\arctan(\frac{x + 1}{6})+C$.
Answer:
$\frac{1}{6}\arctan(\frac{x + 1}{6})+C$