How do I evaluate the integral of the function tan(x) * sin(x) * sin(y) with respect to x and y over the specified limits?

To evaluate the integral of the function tan(x) * sin(x) * sin(y) with respect to x and y over the specified limits, we need to follow these steps:

  1. Understand the function: The function involves a trigonometric identity, and we need to express it in a way that makes integration straightforward. The function can be rewritten using the identity tan(x) = sin(x)/cos(x). Therefore, we have:
  2. tan(x) * sin(x) * sin(y) = (sin(x)/cos(x)) * sin(x) * sin(y) = (sin^2(x) * sin(y)) / cos(x)

  3. Set up the double integral: When integrating with respect to two variables, we typically express the function as ⨍⨍ f(x, y) dy dx. Write the limits of integration for x and y. For example, if integrating over a rectangle defined by [a, b] for x and [c, d] for y, the integral is:
  4. ⨍ from a to b of (⨍ from c to d of (f(x, y) dy) dx

  5. Evaluate the inner integral: Start by evaluating the integral with respect to y:
  6. ⨍ from c to d of ( (sin^2(x) * sin(y)) / cos(x) ) dy

    Using the integral of sin(y), which is -cos(y), we can compute this integral knowing the bounds for y.

  7. Substituting limits: Once you have the indefinite integral, plug in c and d to find:
  8. -1/cos(x) * [cos(d) – cos(c)]

  9. Evaluate the outer integral: Substitute this result back into the integral with respect to x:
  10. ⨍ from a to b of [(-sin^2(x) * (cos(d) – cos(c))) / cos^2(x)] dx

    Now, depending on the range of x, you may apply further trigonometric identities or numerical methods to solve this integral.

  11. The final result: Your final answer will depend on your limits and integration techniques. Make sure to simplify where possible, often using trigonometric identities, numerical methods, or integration rules.

Using these techniques, one can systematically approach the integral of tan(x) * sin(x) * sin(y). Each step must be diligently executed to arrive at the correct solution. To ensure accuracy, consider constantly reviewing calculus principles and integration strategies.

Leave a Comment