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The radius of sphere is increasing at the rate of 0.5mt/sec. Find the rate of increase of its surface area and volume after 3 sec. |
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Answer» Given dr/dt = 0.5 , t = 3sec, ds/dt = ? dv/dt = ? surface area = s = 4πr2 ds/dt = 4π.2r . dr/dt = 4π . 2r . = 4π × 2 × 1.5 × 0.5 = 6π m2 /sec dr = 0.5 × dt ⇒ r = 0.5 t = 0.5 × 3 = 1.5 |
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