Area 'A' of a blot of ink is growing such that after t second its area is given by A = (3t^2

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The area $'A'$ of a blot of ink 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 $t = 2\, sec$. .......... $cm^2/s$

A

$6$

B

$17$

C

$12$

D

$19$

Solution

$\frac{{dA}}{{dt}} = 6\,t$, at $t = 2\,s$, $\frac{{dA}}{{dt}} = 12\,c{m^2}/s$

Standard 11

Physics

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