Welcome to Westonci.ca, where finding answers to your questions is made simple by our community of experts. Experience the convenience of getting reliable answers to your questions from a vast network of knowledgeable experts. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Evaluate the following limit:

[tex]\[ \lim _{x \rightarrow 4}\left(\frac{4-x}{2-\sqrt{x}}\right) \][/tex]


Sagot :

Certainly! Let's find the limit:

[tex]\[ \lim_{x \rightarrow 4}\left(\frac{4-x}{2-\sqrt{x}}\right) \][/tex]

### Step-by-Step Solution:

1. Identify the Type of Limit:
As [tex]\( x \)[/tex] approaches 4, let's examine the expression [tex]\( \frac{4-x}{2-\sqrt{x}} \)[/tex]:
[tex]\[ \frac{4-x}{2-\sqrt{x}} \][/tex]

Substitute [tex]\( x = 4 \)[/tex] into the expression:
[tex]\[ \text{Numerator: } 4 - 4 = 0 \][/tex]
[tex]\[ \text{Denominator: } 2 - \sqrt{4} = 2 - 2 = 0 \][/tex]

So, we get a [tex]\(\frac{0}{0}\)[/tex] indeterminate form.

2. Simplify the Expression:
To eliminate the indeterminate form, we'll rationalize the denominator. Multiply the numerator and the denominator by the conjugate of the denominator [tex]\(2 + \sqrt{x}\)[/tex].

[tex]\[ \frac{4-x}{2-\sqrt{x}} \times \frac{2+\sqrt{x}}{2+\sqrt{x}} = \frac{(4-x)(2+\sqrt{x})}{(2-\sqrt{x})(2+\sqrt{x})} \][/tex]

3. Simplify the Denominator:
The denominator simplifies because it's a difference of squares:
[tex]\[ (2-\sqrt{x})(2+\sqrt{x}) = 4 - x \][/tex]

4. Simplify the Fraction:
Now, the expression becomes:
[tex]\[ \frac{(4-x)(2+\sqrt{x})}{4-x} \][/tex]

Since [tex]\(4 - x \neq 0\)[/tex] when [tex]\(x \neq 4\)[/tex], we can cancel out the [tex]\(4-x\)[/tex] term in the numerator and denominator:
[tex]\[ 2 + \sqrt{x} \][/tex]

5. Evaluate the Limit:
Now that the expression is simplified, substitute [tex]\( x = 4 \)[/tex]:
[tex]\[ 2 + \sqrt{4} = 2 + 2 = 4 \][/tex]

Hence, the limit is:
[tex]\[ \lim_{x \rightarrow 4}\left(\frac{4-x}{2-\sqrt{x}}\right) = 4 \][/tex]

Therefore, the limit is:

[tex]\[ \boxed{4} \][/tex]
Thank you for visiting. Our goal is to provide the most accurate answers for all your informational needs. Come back soon. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Discover more at Westonci.ca. Return for the latest expert answers and updates on various topics.