Applications Of Derivatives Question 381
Question: For the every value of x the function $ f(x)=\frac{1}{5^{x}} $ is
Options:
A) Decreasing
B) Increasing
C) Neither increasing nor decreasing
D) Increasing for x > 0 and decreasing for x < 0
Show Answer
Answer:
Correct Answer: A
Solution:
$ f(x)={5^{-x}} $
therefore $ f’(x)=-{5^{-x}}{\log_{e}}5=-\frac{{\log_{e}}5}{5^{x}} $
therefore $ f’(x)<0 $ for all $ x $ i.e., $ f(x) $ is decreasing for all $ x. $
BETA
