Question:

\[ \int \frac{d x}{\cos x(1+\cos x)}= \]

Show Hint

Split the fraction with partial fractions, then use the half-angle form for the second part.
Updated On: Nov 13, 2026
  • \(\mathrm{log}(\mathrm{sec}x+\mathrm{tan}x)+2\mathrm{tan}(\frac{x}{2})+\mathrm{c}\), where c is the constant of integration

  • \(\mathrm{log}(\mathrm{sec}x+\mathrm{tan}x)-2\mathrm{tan}(\frac{x}{2})+\mathrm{c}\), where c is the constant of integration

  • \(\mathrm{log}(\mathrm{sec}x+\mathrm{tan}x)+\mathrm{tan}(\frac{x}{2})+\mathrm{c}\), where c is the constant of integration

  • \(\mathrm{log}(\mathrm{sec}x+\mathrm{tan}x)-\mathrm{tan}(\frac{x}{2})+\mathrm{c}\), where c is the constant of integration

Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

Step 1: Understanding the Concept
Use \(\dfrac{1}{\cos x(1+\cos x)}=\dfrac{1}{\cos x}-\dfrac{1}{1+\cos x}\).

Step 2: First part
\(\int\sec x\,dx=\log(\sec x+\tan x)\).

Step 3: Second part
\(1+\cos x=2\cos^{2}\dfrac{x}{2}\), so \(\int\dfrac{dx}{1+\cos x}=\dfrac{1}{2}\int\sec^{2}\dfrac{x}{2}\,dx=\tan\dfrac{x}{2}\).

Step 4: Calculation
The integral is \(\log(\sec x+\tan x)-\tan\dfrac{x}{2}+c\).

Final Answer:
The integral is \(\log(\sec x+\tan x)-\tan\frac{x}{2}+c\). \[ \boxed{\text{(D) }\log(\sec x+\tan x)-\tan\left(\dfrac{x}{2}\right)+c} \]
Was this answer helpful?
0
0