Question

Let f be a differentiable function &

f(x + y) = f(x) × f(y) " x, yĪR and f(3) = 3 & f ¢(0) = 11 then f ¢ (3) equals –

• A. 22
• B. 44
• C. 28
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

f ¢(3) = $\underset{h \rightarrow 0}{Lim}\frac{f(3 + h)–f(3)}{h}$

$\underset{h \rightarrow 0}{Lim}f(3)\frac{(f(h)–1)}{h}$ = f(3). f ¢(0) = 3.11 = 33