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Application Of Derivatives

Question
CBSEENMA12035619

If the radius of a sphere is measured as 9 cm with an error of 0.03 cm, then find the approximate error in calculating its volume.

Solution
Let r be the radius of the sphere and ∆r be the error in measuring the radius. Then r = 9cm and ∆ r = 0.03 cm. Now, the volume V of the sphere is given by
                         straight V space equals space 4 over 3 πr cubed space space space space space space space or space space space dV over dr space equals space 4 πr squared
therefore space space space space dV space equals space open parentheses dV over dr close parentheses space increment straight r space equals space left parenthesis 4 πr squared right parenthesis space increment straight r
space space space space space space space space space space space space space space equals space 4 straight pi left parenthesis 9 right parenthesis squared space left parenthesis 0.03 right parenthesis space equals space 9.72 space straight pi space cm cubed
therefore space space space the space approximate space error space in space calculating space the space volume space is space 9.72 space straight pi space cm cubed.