Simple Limits Problem: Finding the Limit of a Square Root Expression

  • Thread starter Saitama
  • Start date
  • Tags
    Limits
In summary, the conversation involves finding the limit of the expression given by ##\sqrt{x+\sqrt{x+\sqrt{x}}}-\sqrt{x}## and rewriting it as ##\sqrt{x}\left(\sqrt{1+\sqrt{\frac{1}{x}\left(1+\frac{1}{\sqrt{x}}\right)}}-1\right)##. The suggested approach is to multiply the expression by ##\frac{\sqrt{x+f(x)}+\sqrt{x}}{\sqrt{x+f(x)}+\sqrt{x}}## and simplify the numerator.
  • #1
Saitama
4,243
93

Homework Statement


Find
[tex]\lim_{x\rightarrow \infty} (\sqrt{x+\sqrt{x+\sqrt{x}}}-\sqrt{x})[/tex]


Homework Equations





The Attempt at a Solution


Rewriting the given expression,
[tex]\sqrt{x}\left(\sqrt{1+\sqrt{\frac{1}{x}\left(1+\frac{1}{\sqrt{x}}\right)}}-1\right)[/tex]
What should I do with the sqrt(x) outside? :confused:

Any help is appreciated. Thanks!
 
Physics news on Phys.org
  • #2
A common way to approach limits of the type of ##\sqrt{x+f(x)}-\sqrt{x}## is a multiplication with ##\displaystyle 1=\frac{\sqrt{x+f(x)}+\sqrt{x}}{\sqrt{x+f(x)}+\sqrt{x}}##. This does not change the limit (as you multiply with 1), but you can simplify the numerator a lot.
 
  • Like
Likes 1 person
  • #3
Pranav-Arora said:

Homework Statement


Find
[tex]\lim_{x\rightarrow \infty} (\sqrt{x+\sqrt{x+\sqrt{x}}}-\sqrt{x})[/tex]

Homework Equations


The Attempt at a Solution


Rewriting the given expression,
[tex]\sqrt{x}\left(\sqrt{1+\sqrt{\frac{1}{x}\left(1+\frac{1}{\sqrt{x}}\right)}}-1\right)[/tex]
What should I do with the sqrt(x) outside? :confused:

Any help is appreciated. Thanks!

I wanted to post earlier but kept messing up my algebra.

Call the expression ##y##. Find ##y.(\sqrt{x + \sqrt{x + \sqrt{x}}} + \sqrt x)##.

mfb has suggested pretty much the same thing.
 
  • Like
Likes 1 person
  • #4
mfb said:
A common way to approach limits of the type of ##\sqrt{x+f(x)}-\sqrt{x}## is a multiplication with ##\displaystyle 1=\frac{\sqrt{x+f(x)}+\sqrt{x}}{\sqrt{x+f(x)}+\sqrt{x}}##. This does not change the limit (as you multiply with 1), but you can simplify the numerator a lot.

Thanks mfb! :smile:
 

1. What is a simple limit problem?

A simple limit problem is a mathematical concept that involves finding the value that a function approaches as the input variable approaches a specific value. This value is known as the limit and can be used to determine the behavior of a function near a given point.

2. How do you solve a simple limit problem?

To solve a simple limit problem, you must first evaluate the function at the given input value. If the resulting value is undefined or indeterminate, you can use algebraic manipulation or other techniques such as L'Hopital's rule to simplify the function and find the limit.

3. What is the difference between a one-sided and two-sided limit?

A one-sided limit only considers the behavior of the function as the input variable approaches the given value from one direction, either the left or right. A two-sided limit, on the other hand, takes into account the behavior of the function from both directions.

4. What are some common techniques for finding limits?

Some common techniques for finding limits include direct substitution, factoring, rationalizing the numerator or denominator, and using special trigonometric limits. L'Hopital's rule is also a useful tool for evaluating limits of indeterminate forms.

5. Why are limits important in mathematics?

Limits are important in mathematics because they allow us to understand the behavior of a function near a specific point, even if the function is undefined at that point. They are also crucial in calculus, as they are used to define derivatives and integrals, which are essential concepts in many areas of science and engineering.

Similar threads

  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
948
  • Calculus and Beyond Homework Help
Replies
13
Views
681
  • Calculus and Beyond Homework Help
Replies
8
Views
792
  • Calculus and Beyond Homework Help
Replies
4
Views
958
  • Calculus and Beyond Homework Help
Replies
16
Views
1K
  • Calculus and Beyond Homework Help
Replies
14
Views
632
  • Calculus and Beyond Homework Help
Replies
8
Views
900
  • Calculus and Beyond Homework Help
Replies
7
Views
997
  • Calculus and Beyond Homework Help
Replies
7
Views
609
Back
Top