Definite Integration Question 424

Question: If the area above the x-axis, bounded by the curves $ y=2^{kx} $ and $ x=0 $ and $ x=2 $ is $ \frac{3}{\ln 2}, $ then the value of k is

[Orissa JEE 2003]

Options:

A) $ \frac{1}{2} $

B) 1

C) $ -1 $

D) 2

Show Answer

Answer:

Correct Answer: B

Solution:

$ \int _{0}^{2}{2^{kx}dx=\frac{3}{\log 2}\Rightarrow 2^{2k}-1=3k} $ . Now check from options, only satisfies the above condition.