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Need Solution for R.D.Sharma Maths Class 12 Chapter 21 Differential Equations Exercise Revision Exercise Question 24 Maths Textbook Solution.

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Answer:y=log|\tan ^{2}+2\tan x+5|+C

Hint:  Use substitution method

Given:\left(\tan ^{2} x+2 \tan x+5\right) \frac{d y}{d x}=2(1+\tan x) \sec ^{2} x

Solution: \left(\tan ^{2} x+2 \tan x+5\right) \frac{d y}{d x}=2(1+\tan x) \sec ^{2} x

              \Rightarrow \quad d y=\frac{\left.2(1+\tan x) \sec ^{2} x\right)}{\left(\tan ^{2} x+2 \tan x+5\right)} d x

Integrating both sides, we get,

\Rightarrow \quad\int d y=\frac{\left.2(1+\tan x) \sec ^{2} x\right)}{\left(\tan ^{2} x+2 \tan x+5\right)} d x

Let,\tan ^{2}x+2\tan x+5=t

Differentiate w.r.t x

\begin{aligned} &\left(2 \tan x \sec ^{2} x+2 \sec ^{2} x\right) d x=d t \\ &\Rightarrow 2(1+\tan x) \sec ^{2} x d x=d t \\ &\Rightarrow \int d y=\int \frac{1}{t} d t \\ &\Rightarrow y=\log |t|+C \\ &\Rightarrow y=\log \left|\tan ^{2}+2 \tan x+5\right|+C \end{aligned}

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