. If l is the side of a square and dl/dt =0.2 m/s ,then what is the rate of increase in area when l=5m ? i)2m²/s ii) 1m²/s iii)4m²/s iv)3m²/s

Question

. If l is the side of a square and dl/dt =0.2 m/s ,then what is the rate of increase in area when l=5m ? i)2m²/s  ii) 1m²/s  iii)4m²/s  iv)3m²/s

hartnn · Answer

Area of square A = l^2
Rate of Increase in Area = dA/dt = (dA/dl)* (dl/dt) = ....?

anonymous · Answer

Yes!!! i GOT AN answer.
we need to find ; dA/dt=?
Now, 
dA/dt=d(l^2)/dt
        =2l*dl/dt
        = 2*5*0.2
        = 2
hence, answer is 1

hartnn · Answer

thats correct! good work :)