Example 9 - Chapter 7 Class 12 Integrals - Part 3

Example 9 - Chapter 7 Class 12 Integrals - Part 4
Example 9 - Chapter 7 Class 12 Integrals - Part 5
Example 9 - Chapter 7 Class 12 Integrals - Part 6


Transcript

Example 9 Find the following integrals: (ii) ∫1▒𝑑𝑥/(〖3𝑥〗^2−13𝑥 + 10) ∫1▒𝑑𝑥/(〖3𝑥〗^2 − 13𝑥 + 10) Solving denominator 〖3𝑥〗^2+13𝑥−10 =3(𝑥^2+13/3 𝑥 −10/3) =3(𝑥^2+2. 𝑥× 13/6 −10/3) Adding and subtracting (13/6)^2 =3(𝑥^2+2. 𝑥× 13/6+(13/6)^2−10/3−(13/6)^2 ) =3((𝑥+13/6)^2−10/3−(169/36)) =3((𝑥+13/6)^2−(10/3 +169/36)) =3((𝑥+13/6)^2−((120 +169)/36 )) =3((𝑥+13/6)^2−289/36) =3((𝑥+13/6)^2−(17/6)^2 ) Hence, our equation becomes ∫1▒𝑑𝑥/(〖3𝑥〗^2 − 13𝑥 + 10) = 1/3 ∫1▒𝑑𝑥/((𝑥 + 13/6)^2− (17/6)^2 ) It is of form ∫1▒〖𝑑𝑥/(𝑥^2 − 𝑎^2 )=1/2𝑎 𝑙𝑜𝑔|(𝑥 − 𝑎)/(𝑥 + 𝑎)|+𝐶1〗 Replacing 𝑥 by (𝑥+13/6)𝑎𝑛𝑑 𝑎 𝑏𝑦 17/6, = 1/3 × 1/2(17/6) ×log⁡|(𝑥 + 13/6 − 17/6)/(𝑥+ 13/6 + 17/6)| + C = 1/3 × 6/2(17) ×log⁡|((6𝑥 + 13 − 17)/6)/((6𝑥 +13 + 17)/6)| + C = 1/17 log⁡|(6𝑥 − 4)/(6𝑥 + 30)| + C = 1/17 log⁡|(2(3𝑥 − 2))/(6(𝑥 + 5))|+ C = 1/17 log⁡|( (3𝑥 − 2))/(3(𝑥 + 5))|+ C = 1/17 log⁡|( (3𝑥 − 2))/((𝑥 + 5))|−1/17 log⁡3 + C = 𝟏/𝟏𝟕 𝒍𝒐𝒈⁡|( (𝟑𝒙 − 𝟐))/((𝒙 + 𝟓))|+ C1

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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, Social Science, Physics, Chemistry, Computer Science at Teachoo.