Chapter 7 Class 12 Integrals
Chapter 7 Class 12 Integrals
Last updated at July 14, 2026 by Teachoo
Transcript
Ex 7.9, 9 The value of the integral ā«_(1/3)^1āć (š„ āš„^3 )^(1/3)/š„^4 ć šš„ is 6 (B) 0 (C) 3 (D) 4 ā«_(1/3)^1āć (š„ ā š„^3 )^(1/3)/š„^4 ć šš„ Taking common š„^3 from numerator = ā«_(1/3)^1āć ((š„^3 )^(1/3) (1/š„^2 ā1)^(1/3))/š„^4 ć šš„ = ā«_(1/3)^1āć (š„ (1/š„^2 ā1)^(1/3))/š„^4 ć šš„ = ā«_(1/3)^1āć ( (1/š„^2 ā1)^(1/3))/š„^3 ć šš„ Let t = 1/š„^2 ā1 šš”/šš„=(ā2)/š„^3 (āšš”)/2=šš„/š„^3 Thus, when x varies from 1/3 to 1, t varies form 0 to 8 Substituting values, ā«_(1/3)^1āć ( (1/š„^2 ā1)^(1/3))/š„^3 ć šš„ = 1/2 ā«_8^0āćš”^(1/3) šš”ć = (ā1)/2 [š”^(1/3 + 1)/(1/3 + 1)]_8^0 = (ā1)/2 [ć3š”ć^(4/3 )/4]_8^0 Putting limits = (ā1)/2 (0ā(3(8)^(4/3))/4) = 1/2 (3/4) (8)^(4/3) = 1/2 (3/4) (2^3 )^(4/3) = 1/2 (3/4) (2^4 ) = 6 So, (A) is the correct answer.