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Ex 6.4, 5 - Find approx change in surface area of cube of side x

Ex 6.4,5 - Chapter 6 Class 12 Application of Derivatives - Part 2

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Ex 6.4, 5 Find the approximate change in the surface area of a cube of side x meters caused by decreasing the side by 1%.Let side of the cube = x meters. Given Decrease in side = 1% = − 0.01 x Hence, ∆ x = −0.01 x Surface area of the cube = S = 6x2 m2 We need to find the approximate change in the surface area of the cube i.e. ∆ S Now, ∆ S = 𝑑𝑠/𝑑𝑥 ∆x = 𝑑(6𝑥^2 )/𝑑𝑥 ∆x = 12x (−0.01x) = − 0.12x2 Hence, the approximate change is 0.12x2 m2

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.