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Evaluate the limit as [tex]\( x \)[/tex] approaches 0:

[tex]\[ \lim_{x \rightarrow 0} \frac{\sqrt{x+3}-\sqrt{3}}{x} \][/tex]


Sagot :

Sure, let's solve the limit [tex]\( \lim_{x \to 0} \frac{\sqrt{x + 3} - \sqrt{3}}{x} \)[/tex] step-by-step.

1. Identify the Indeterminate Form:
First, let's substitute [tex]\( x = 0 \)[/tex] directly into the expression to see what we get:

[tex]\[ \frac{\sqrt{0 + 3} - \sqrt{3}}{0} = \frac{\sqrt{3} - \sqrt{3}}{0} = \frac{0}{0} \][/tex]

We obtain an indeterminate form [tex]\(\frac{0}{0}\)[/tex].

2. Apply Algebraic Manipulation (Rationalization):
To resolve this indeterminate form, we can apply a trick called rationalization. Multiply the numerator and the denominator by the conjugate of the numerator:

[tex]\[ \frac{\sqrt{x + 3} - \sqrt{3}}{x} \cdot \frac{\sqrt{x + 3} + \sqrt{3}}{\sqrt{x + 3} + \sqrt{3}} \][/tex]

3. Simplify the Expression:
This will result in the following expression:

[tex]\[ \frac{(\sqrt{x + 3} - \sqrt{3})(\sqrt{x + 3} + \sqrt{3})}{x (\sqrt{x + 3} + \sqrt{3})} \][/tex]

The numerator simplifies using the difference of squares:

[tex]\[ (\sqrt{x + 3})^2 - (\sqrt{3})^2 = (x + 3) - 3 = x \][/tex]

So, we have:

[tex]\[ \frac{x}{x (\sqrt{x + 3} + \sqrt{3})} = \frac{1}{\sqrt{x + 3} + \sqrt{3}} \][/tex]

4. Evaluate the Limit:
Now we evaluate the limit as [tex]\( x \)[/tex] approaches 0:

[tex]\[ \lim_{x \to 0} \frac{1}{\sqrt{x + 3} + \sqrt{3}} \][/tex]

Substitute [tex]\( x = 0 \)[/tex]:

[tex]\[ \frac{1}{\sqrt{0 + 3} + \sqrt{3}} = \frac{1}{\sqrt{3} + \sqrt{3}} = \frac{1}{2\sqrt{3}} \][/tex]

5. Simplify the Final Result:
Simplify the reciprocal expression:

[tex]\[ \frac{1}{2\sqrt{3}} = \frac{1}{2} \cdot \frac{1}{\sqrt{3}} = \frac{1}{2} \cdot \frac{\sqrt{3}}{3} = \frac{\sqrt{3}}{6} \][/tex]

Hence, the limit is:

[tex]\[ \lim_{x \to 0} \frac{\sqrt{x + 3} - \sqrt{3}}{x} = \frac{\sqrt{3}}{6} \][/tex]