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Find d∫x2x4+3x2+2dx - Mathematics

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Question

Find `int x^2/(x^4 + 3x^2 + 2) "d"x`

Sum
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Solution

Put x2 = t

Then 2x dx = dt.

Now I = `int (x^3"d"x)/(x^4 + 3x^2 + 2)`

= `1/2 int  "tdt"/("t"^2 + 3"t" + 2)`

Consider `"t"/("t"^2 + 3"t" + 2) = "A"/("t" + 1) + "B"/("t" + 2)`

Comparing coefficient, we get A = –1, B = 2.

Then I = `1/2[2 int "dt"/("t" + 2) - int "dt"/("t" + 1)]`

= `1/2 [2log|"t" + 2| - log|"t" + 1|]`

= `log|(x^2 + 2)/sqrt(x^2 + 1)| + "C"`

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Definite Integrals
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Chapter 7: Integrals - Solved Examples [Page 149]

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NCERT Exemplar Mathematics [English] Class 12
Chapter 7 Integrals
Solved Examples | Q 7 | Page 149

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