Question:

Evaluate the integral: \[ \int \frac{\sin x + \cos x}{\sin x - \cos x} \, dx =\ ? \]

Show Hint

When the numerator is the derivative of the denominator, use substitution to convert the integral into a logarithmic form.
Updated On: Jun 4, 2025
  • \(-x + \log|\cos x - \sin x| + c\)
  • \(x - \log|\cos x - \sin x| + c\)
  • \(-\log|\cos x - \sin x| + c\)
  • \(\log|\cos x - \sin x| + c\)
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

We are given: \[ \int \frac{\sin x + \cos x}{\sin x - \cos x} \, dx \] Let us use substitution. Let: \[ u = \sin x - \cos x \Rightarrow \frac{du}{dx} = \cos x + \sin x \] So, \[ \frac{\sin x + \cos x}{\sin x - \cos x} \, dx = \frac{du}{u} \] Now integrate: \[ \int \frac{du}{u} = \log|u| + c = \log|\sin x - \cos x| + c \] Hence, \[ \int \frac{\sin x + \cos x}{\sin x - \cos x} \, dx = \boxed{\log|\cos x - \sin x| + c} \]
Was this answer helpful?
0
0