MCQ
If $f(r) = \pi {r^2}$, then $\mathop {\lim }\limits_{h \to 0} \frac{{f(r + h) - f(r)}}{h} = $
- A$\pi {r^2}$
- ✓$2\pi r$
- C$2\pi $
- D$2\pi {r^2}$
✓
Answer
Correct option: B.
$2\pi r$
b
(b)$\frac{d}{{dr}}f(r) = 2\pi r$.
(b)$\frac{d}{{dr}}f(r) = 2\pi r$.
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