What is the Minimum Value of f(x) for Positive Real Numbers x and y?

In summary, the conversation is about proving the inequality \frac{1}{1+\sqrt{x}}+\frac{1}{1+\sqrt{y}} \geq \frac{2\sqrt{2}}{1+\sqrt{2}} for all positive real numbers x and y. It is mentioned that no proof is possible and an example is given to show that the left hand side can be less than the right hand side. The conversation then shifts to finding the minimum value of a function involving x and y, and it is mentioned that this involves finding the critical points.
  • #1
mathlover1
8
0
For all positive real numbers [tex]x,y[/tex] prove that:

[tex] \frac{1}{1+\sqrt{x}}+\frac{1}{1+\sqrt{y}} \geq \frac{2\sqrt{2}}{1+\sqrt{2}}[/tex]
 
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  • #2


mathlover1 said:
For all positive real numbers [tex]x,y[/tex] prove that:

[tex] \frac{1}{1+\sqrt{x}}+\frac{1}{1+\sqrt{y}} \geq \frac{2\sqrt{2}}{1+\sqrt{2}}[/tex]

No proof is possible.
Let x=y=1, then left hand side is equal to 1 which is strictly less than the right hand side.
 
  • #3


ohubrismine said:
No proof is possible.
Let x=y=1, then left hand side is equal to 1 which is strictly less than the right hand side.

I forgot to say that x,y are numbers such that x+y=1
 
  • #4


Since x+y=1, y=1-x. Now, you are looking for the minimum. How would you do it?
 
  • #5


Tedjn said:
Since x+y=1, y=1-x. Now, you are looking for the minimum. How would you do it?
That's why i am asking to you guys!
This inequality is correct .. just need to be proven!
 
  • #6


Find the minimum value of
[tex]f(x) = \frac{1}{1 + \sqrt{x} } + \frac{1}{1 + \sqrt{1 - x}}[/tex]

This involves finding the critical points.
 

Related to What is the Minimum Value of f(x) for Positive Real Numbers x and y?

1. What does "for all positive real numbers" mean?

"For all positive real numbers" means that the statement or equation is true for any number greater than 0 that can be expressed as a decimal or fraction. It includes all numbers between 0 and infinity, but does not include negative numbers.

2. Why is "for all positive real numbers" important in scientific research?

When conducting scientific research, it is important to consider all possible values and scenarios. By including "for all positive real numbers" in our statements or equations, we ensure that our findings and conclusions are applicable to a wide range of values and not just limited to a specific set of numbers.

3. Can "for all positive real numbers" be replaced with "for all real numbers"?

No, "for all positive real numbers" and "for all real numbers" are not interchangeable. While "for all real numbers" includes all positive numbers, it also includes negative numbers and zero. This can significantly change the outcome or validity of a statement or equation.

4. How does "for all positive real numbers" differ from "for all positive integers"?

"For all positive real numbers" includes all numbers between 0 and infinity, including fractions and decimals. "For all positive integers" only includes whole numbers that are greater than 0. This means that "for all positive integers" is a subset of "for all positive real numbers".

5. Can "for all positive real numbers" be proven mathematically?

Yes, "for all positive real numbers" can be proven mathematically using various methods such as induction, contradiction, or direct proof. However, it is important to note that the proof may vary depending on the specific statement or equation being examined.

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