MCQ
$\lim _{x \rightarrow 0} \frac{5^x-4^x}{4^x-3^x}$ is equal to
  • A
    $0$
  • $\frac{\log \left(\frac{5}{4}\right)}{\log \left(\frac{4}{3}\right)}$
  • C
    1
  • D
    $\log \left(\frac{5}{4}\right)$

Answer

Correct option: B.
$\frac{\log \left(\frac{5}{4}\right)}{\log \left(\frac{4}{3}\right)}$
(B)
$\lim _{x \rightarrow 0} \frac{5^x-4^x}{4^x-3^x}=\lim _{x \rightarrow 0} \frac{\left(\frac{5^x-1}{x}\right)-\left(\frac{4^x-1}{x}\right)}{\left(\frac{4^x-1}{x}\right)-\left(\frac{3^x-1}{x}\right)}$
$=\frac{\log 5-\log 4}{\log 4-\log 3}$
$=\frac{\log \left(\frac{5}{4}\right)}{\log \left(\frac{4}{3}\right)}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free