Find f log x (1 + log x) 2 dx

This question is similar to Ex 7.2, 35 - Chapter 7 Class 12 - Integrals

[Sample Paper Term 2] Find Integration  ∫ π‘™π‘œπ‘”π‘₯ (1+π‘™π‘œπ‘”π‘₯) 2 𝑑x - CBSE Class 12 Sample Paper for 2022 Boards (For Term 2)

part 2 - Question 1 (Choice 1) - CBSE Class 12 Sample Paper for 2022 Boards (For Term 2) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12
part 3 - Question 1 (Choice 1) - CBSE Class 12 Sample Paper for 2022 Boards (For Term 2) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12

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Question 1 – Choice 1 Find ∫1β–’γ€–log⁑π‘₯/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€—Let 𝐈=∫1β–’γ€–log⁑π‘₯/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€— =∫1β–’γ€–(π’π’π’ˆβ‘π’™ + 𝟏 βˆ’ 𝟏)/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€— =∫1β–’γ€–((1 + log⁑π‘₯) βˆ’ 1)/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€— =∫1β–’γ€–((1 + log⁑π‘₯) )/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€—βˆ’βˆ«1β–’γ€–1/(1 + log⁑π‘₯ )^2 𝑑π‘₯γ€— =∫1β–’γ€–(𝟏 )/((𝟏 + π’π’π’ˆβ‘π’™ ) ) π’…π’™γ€—βˆ’βˆ«1β–’γ€–πŸ/(𝟏 + π’π’π’ˆβ‘π’™ )^𝟐 𝒅𝒙〗 Solving ∫1β–’γ€–(𝟏 )/((𝟏 + π₯𝐨𝐠⁑𝐱 ) ) 𝐝𝐱〗 Using Integration by parts ∫1β–’γ€–(𝟏 )/((𝟏 + π’π’π’ˆβ‘π’™ ) ) 𝒅𝒙〗 = ∫1β–’γ€–(1 )/((1 + π‘™π‘œπ‘”β‘π‘₯ ) ) Γ— 1 𝑑π‘₯γ€— = 1/((1 + log⁑π‘₯)) ∫1β–’γ€–1 𝑑π‘₯γ€—βˆ’βˆ«1β–’(𝒅(𝟏/(𝟏 + π’π’π’ˆ 𝒙))/𝒅𝒙 ∫1β–’γ€–πŸ 𝒅𝒙〗) 𝒅𝒙 = 1/((1 + log⁑π‘₯))Γ— π‘₯βˆ’βˆ«1β–’((βˆ’πŸ)/(𝟏 +π’π’π’ˆ 𝒙)^𝟐 Γ—πŸ/𝒙 Γ— 𝒙) 𝒅𝒙 = π‘₯/((1 + log⁑π‘₯))+∫1β–’πŸ/(𝟏 + π’π’π’ˆ 𝒙)^𝟐 𝒅𝒙We know that ∫1▒〖𝑓(π‘₯) 𝑔⁑(π‘₯) γ€— 𝑑π‘₯=𝑓(π‘₯) ∫1▒𝑔(π‘₯) 𝑑π‘₯βˆ’βˆ«1β–’(𝑓^β€² (π‘₯) ∫1▒𝑔(π‘₯) 𝑑π‘₯) 𝑑π‘₯ Putting f(x) = 1/(1 + log x) and g(x) = 1 Thus I=∫1β–’γ€–(1 )/((1 + π‘™π‘œπ‘”β‘π‘₯ ) ) 𝑑π‘₯γ€—βˆ’βˆ«1β–’γ€–1/(1 + π‘™π‘œπ‘”β‘π‘₯ )^2 𝑑π‘₯γ€— = π‘₯/((1 + log⁑π‘₯))+∫1β–’1/(1 + π‘™π‘œπ‘” π‘₯)^2 𝑑π‘₯βˆ’βˆ«1β–’γ€–1/(1 + π‘™π‘œπ‘”β‘π‘₯ )^2 𝑑π‘₯γ€— = 𝒙/((𝟏 + π’π’π’ˆβ‘π’™))+π‘ͺ

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Davneet Singh

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