Question

Ametallic disc is being heated.Its area A(in metre square)at any time t(in second)is given by A=5t^2+4t+8.The rate of increase in area at t=3 is
1)30m^2/s. 2)34m^2/s​

Answer 1

Your answer mate

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Given, area is dependent on time as, A=5t2+4t+8

So, rate of increase in area = dAdt=d(5t2+4t+8)dt=10t+4

So, ∣∣∣dAdt∣∣∣3s=10⋅3+4=34m2s

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