How fast the area of a circle increases when its radius is 5cm. (i) re – InterviewSolution

1.	How fast the area of a circle increases when its radius is 5cm. (i) respect to radius (ii) with respect to diameter.
Answer» (i)`A =pir^(2) ," "(dA)/(dr) =2pir` `:. (dA)/(dr)]_(r=5) " " =10 pi cm^(2)//cm.` `(ii) A =(pi)/(4) D^(2) , (dA)/(dD) =(pi)/(2)D` `:. (dA)/(dD)]_(D=10)=(pi)/(2). 10=5pi cm^(2)//cm.`

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