Trigonometric Equations Question 69
Question: The number of solution of the equation $ 2\cos (e^{x})=5^{x}+{5^{-x}} $ , are
[UPSEAT 2004; IIT 1992]
Options:
A) No solution
B) One solution
C) Two solutions
D) Infinitely many solutions
Show Answer
Answer:
Correct Answer: A
Solution:
- We know $ \frac{5^{x}+{5^{-x}}}{2}\ge 1 $ , (using A.M. $ \ge $ G.M.) But since $ cos,(e^{x})\le 1 $ So, there does not exist any solution.
BETA
