Example 13 - Find integral 3x - 2 / (x + 1)2 (x + 3) dx - Examples

Example 13 - Chapter 7 Class 12 Integrals - Part 2
Example 13 - Chapter 7 Class 12 Integrals - Part 3
Example 13 - Chapter 7 Class 12 Integrals - Part 4
Example 13 - Chapter 7 Class 12 Integrals - Part 5

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Example 13 Find ∫1ā–’(3š‘„ āˆ’2)/((š‘„ + 1)^2 (š‘„ + 3) ) š‘‘š‘„ We can write Integral as (3š‘„ āˆ’ 2)/((š‘„ + 1)^2 (š‘„ + 3) )=š“/(š‘„ + 1) + šµ/(š‘„ + 1)^2 + š¶/((š‘„ + 3) ) (3š‘„ āˆ’ 2)/((š‘„ + 1)^2 (š‘„ + 3) )=(š“(š‘„ + 1)(š‘„ + 3) + šµ(š‘„ + 3) + š¶(š‘„ + 1)^2)/((š‘„ + 1)^2 (š‘„ + 3) ) Cancelling denominator 3š‘„ āˆ’2=š“(š‘„+1)(š‘„+3)+šµ(š‘„+3)+š¶(š‘„+1)^2 Putting x = āˆ’1 3(āˆ’1) āˆ’2=š“(āˆ’1+1)(āˆ’1+3)+šµ(āˆ’1+3)+š¶(āˆ’1+1)^2 āˆ’3āˆ’2=š“Ć—0+šµĆ—2+š¶Ć—(0)^2 āˆ’5=šµĆ—2 šµ=(āˆ’ 5)/2 Putting x = āˆ’ 3 3š‘„ āˆ’2=š“(š‘„+1)(š‘„+3)+šµ(š‘„+3)+š¶(š‘„+1)^2 3(āˆ’3)āˆ’2=š“(āˆ’3+1)(āˆ’3+3)+šµ(āˆ’3+3)+š¶(āˆ’3+1)^2 āˆ’9āˆ’2=š“Ć—0+šµĆ—0+š¶Ć—(āˆ’2)^2 āˆ’11=0+0+š¶(4) āˆ’11=4š¶ (āˆ’11)/4 =š¶ š¶ =(āˆ’11)/4 Putting x = 0 3š‘„ āˆ’2=š“(š‘„+1)(š‘„+3)+šµ(š‘„+3)+š¶(š‘„+1)^2 3(0) āˆ’ 2 = A(1) (3) + B(3) + C 怖"(1)" 怗^2 āˆ’2 = 3A + 3B + C Putting value of B & C āˆ’2 = 3A + 3((āˆ’5)/2) + ((āˆ’11)/4) āˆ’2 = 3A āˆ’ 15/2āˆ’11/4 āˆ’2 = 3A + (āˆ’30 āˆ’ 11)/4 āˆ’8 = 12A āˆ’ 41 41 āˆ’ 8 = 12A 33/12 = A 11/4 = A Hence, we can write (3š‘„ āˆ’ 2)/((š‘„ + 1)^2 (š‘„ + 3) )=š“/(š‘„ + 1) + šµ/(š‘„ + 1)^2 + š¶/((š‘„ + 3) ) (3š‘„ āˆ’ 2)/((š‘„ + 1)^2 (š‘„ + 3) )=11/4(š‘„ + 1) āˆ’ 5/怖2(š‘„ + 1)怗^2 āˆ’ 11/4(š‘„ + 3) Therefore ∫1ā–’(3š‘„ āˆ’ 2)/((š‘„ + 1)^2 (š‘„ + 3) ) š‘‘š‘„ =∫1ā–’11/4(š‘„ + 1) š‘‘š‘„āˆ’āˆ«1ā–’5/怖2(š‘„ + 1)怗^2 š‘‘š‘„āˆ’āˆ«1ā–’11/4(š‘„ + 3) š‘‘š‘„ =11/4 log⁔|š‘„+1|āˆ’5/2Ɨ((āˆ’1))/((š‘„ + 1) ) āˆ’ 11/4 log⁔|š‘„+3|+š¶ =11/4 (log⁔|š‘„+1|āˆ’log⁔|š‘„+3| )+5/(2 (š‘„ + 1) )+š¶ =šŸšŸ/šŸ’ š’š’š’ˆā”|(š’™ + šŸ)/(š’™ + šŸ‘)| + šŸ“/(šŸ (š’™ + šŸ) )+š‘Ŗ

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo