Question:hard

The value of the integral \(\int \frac{dx}{3+\sin 2x+\sin ^{2}x}=\) .........

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Divide numerator and denominator by cos squared x and substitute t equal to tan x.
Updated On: Nov 12, 2026
  • \(\frac{1}{\sqrt{13}}\tan ^{-1}\left(\frac{4\,\tan x+1}{\sqrt{13}}\right)+c\)
  • \(\frac{2}{\sqrt{11}}\tan ^{-1}\left(\frac{4\,\tan x+2}{\sqrt{11}}\right)+c\)
  • \(\frac{1}{11}\tan ^{-1}\left(\frac{2\,\tan x+1}{11}\right)+c\)
  • \(\frac{1}{\sqrt{11}}\tan ^{-1}\left(\frac{4\,\tan x+1}{\sqrt{11}}\right)+c\)
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Rewrite the denominator
Use $\sin2x=2\sin x\cos x$ and $3=3\sin^{2}x+3\cos^{2}x$.
The denominator is $4\sin^{2}x+2\sin x\cos x+3\cos^{2}x$.

Step 2: Substitute t = tan x
Dividing by $\cos^{2}x$ and using $dt=\sec^{2}x\,dx$: $\int\frac{dt}{4t^{2}+2t+3}$.

Step 3: Standard form
$\int\frac{dt}{at^{2}+bt+c}$ with $4ac-b^{2}=48-4=44$ gives $\frac{2}{\sqrt{44}}\tan^{-1}\frac{8t+2}{\sqrt{44}}=\frac{1}{\sqrt{11}}\tan^{-1}\frac{4t+1}{\sqrt{11}}$.

Final Answer:
So the result is the same expression with root 11 and (4 tan x + 1). \[ \boxed{\text{(D) }\dfrac{1}{\sqrt{11}}\tan ^{-1}\left(\dfrac{4\,\tan x+1}{\sqrt{11}}\right)+c} \]
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