1A = \pi r^{2}
dAdt = 2\pi rdrdt
→ dAdt = 2 x \pi% x 20 x 5 = 200\pi%
hence (b)
If the rate of increase of the radius of a circle is 5 cm/.sec., then the rate of increase of its area, when the radius is 20 cm, will be
(A) 10Ï€ (B) 20Ï€ (C) 200Ï€ (D) 400Ï€
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3 Answers
1
1yeh sab kya hai bhai
cant u do a silly board level Q on ur own...
dont take it that way but this is problem that shudnt be asked here........
atleast maintain some level ;)
39Che I believe this is just someone's fake profile...he is posting problems to make himself above suspicion.
Nishant bhaiya (aided by me) did a cleanup of most of those fake profiles today.