Question
Question: Given that f is a real-valued differential function such that f(x).f '(x) \< 0 for all real x, it fo...
Given that f is a real-valued differential function such that f(x).f '(x) < 0 for all real x, it follows that
A
f(x) is an increasing function
B
f(x) is a decreasing function
C
|f(x)| is an increasing function
D
|f(x)| is a decreasing function
Answer
|f(x)| is a decreasing function
Explanation
Solution
Qf(x) f '(x) < 0
But – f(x) decreasing