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The area of a blot of inkk is growing su...

The area of a blot of inkk is growing such that after t second , its area is given by `A=(3t^2 +7)cm^2` . Calculate the rate of increase of area at t = 5seconds.

Text Solution

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`A= pir^2, Da/dr=d/dr(pir^2)`
` pi xx2r =2pir`
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