A = πr^2
∆A ≈ dr ∆r = 2π*40*(49-40) = 720π
actual change is π(49^2 - 40^2) = 801π
not very close, since ∆r is so big.
The shape of a colony of bacteria on a Petri dish is circular. Find the approximate increase in its area if its radius increases from 40 mm to 49 mm.
The estimated change in area is nothing mm2.
1 answer