alleryStart learning →A disc has radius r and area πr². Compute dA/dr when r = 6 cm.
A6π cm²/cm
B36π cm²/cm
C24π cm²/cm
D12π cm²/cm
Answer & Solution
Correct answer: D. 12π cm²/cm
A = πr² gives dA/dr = 2πr, which is 12π at r = 6.
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