Example 1 - Chapter 6 Class 12 Application of Derivatives

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Example 1 - Find rate of change of area of circle per second - Examples

part 2 - Example 1 - Examples - Serial order wise - Chapter 6 Class 12 Application of Derivatives

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Example 1 Find the rate of change of the area of a circle per second with respect to its radius r when r = 5 cm.We have to find rate of change of area of circle with respect to radius i.e. we need to find (š’…(š‘Øš’“š’†š’‚ š’š’‡ š’„š’Šš’“š’„š’š’†))/(š’… (š’“š’‚š’…š’Šš’–š’” š’š’‡ š’„š’Šš’“š’„š’š’†)) = š’…š‘Ø/š’…š’“ We know that Area of circle = Ļ€ r2 A = Ļ€r2 Finding š’…š‘Ø/š’…š’“ š‘‘š“/š‘‘š‘Ÿ = (š‘‘(šœ‹š‘Ÿ2))/š‘‘š‘Ÿ = Ļ€ ((š‘Ÿ2))/š‘‘š‘Ÿ = Ļ€ (2r) = 2Ļ€r For r = 5 cm š‘‘š“/š‘‘š‘Ÿ = 2Ļ€ (5) = 10Ļ€ cmx/s

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