Problem 33

Question

Determine whether the improper integral diverges or converges. Evaluate the integral if it converges, and check your results with the results obtained by using the integration capabilities of a graphing utility. $$ \int_{0}^{\pi / 2} \tan \theta d \theta $$

Step-by-Step Solution

Verified
Answer
The improper integral diverges.
1Step 1: Understand the function behavior
As \(\theta\) approaches \(\pi / 2\) from the left, \(\tan \theta\) approaches \(\infty\). Thus, the integral has an infinite discontinuity at \(\pi / 2\), and hence it is an improper integral.
2Step 2: Solve the Integral
We use the result that the integral of \(\tan \theta\) is \(-\ln |\cos \theta|\), so we have \(-\ln |\cos \theta|\) for \(0\) to \(\pi / 2\). Evaluation at the limits gives \(-\ln |\cos (\pi / 2)| + \ln |\cos (0)| = -\ln |0| + \ln |1| = -\ln 0\). Since \(\ln 0\) is undefined, the integral is also undefined.
3Step 3: Convergence/Divergence
Because the integral is undefined, we say that the improper integral diverges.