Math, asked by Anonymous, 5 hours ago


\sf\fbox\pink{❥︎QuestioN}
\sf\red{lim}  \: x→2 \: \red{ \frac{( {x}^{2} - 4) }{ \sqrt{3}x - 2 -  \sqrt{x}   + 2}}


\sf\fbox\green{❥︎need \: quality \: answer}
\sf\fbox\purple{❥︎dont \: spam}

Answers

Answered by mathdude500
5

\large\underline{\sf{Solution-}}

Given expression is

\rm :\longmapsto\:\displaystyle\lim_{x \to 2}\rm  \frac{ {x}^{2}  - 4}{ \sqrt{3x - 2}  -  \sqrt{x + 2} }

If we substitute directly x = 2, we get

 \rm \:  =  \:   \dfrac{ {2}^{2}  - 4}{ \sqrt{3(2) - 2}  -  \sqrt{2 + 2} }

 \rm \:  =  \:   \dfrac{ 4  - 4}{ \sqrt{6 - 2}  -  \sqrt{4} }

 \rm \:  =  \:   \dfrac{0}{ \sqrt{4}  - 2}

 \rm \:  =  \:   \dfrac{0}{ 2  - 2}

 \rm \:  =  \:   \dfrac{0}{0}

which is indeterminant form.

So,

\rm :\longmapsto\:\displaystyle\lim_{x \to 2}\rm  \frac{ {x}^{2}  - 4}{ \sqrt{3x - 2}  -  \sqrt{x + 2} }

On rationalizing the denominator, we get

\rm \:  = \displaystyle\lim_{x \to 2}\rm  \frac{ {x}^{2}  -  {2}^{2} }{ \sqrt{3x - 2}  -  \sqrt{x + 2} } \times \dfrac{ \sqrt{3x - 2}  +  \sqrt{x + 2} }{ \sqrt{3x - 2}  +  \sqrt{x + 2} }

We know

\boxed{\tt{  \: (x + y)(x - y) \:  =  \:  {x}^{2}  -  {y}^{2} \: }}

So, above can be rewritten as

 \rm \:  =  \: \displaystyle\lim_{x \to 2}\rm  \frac{(x - 2)(x + 2)[ \sqrt{3x - 2} +  \sqrt{x + 2}]}{(3x - 2) - (x + 2)}

 \rm \:  =  \: \displaystyle\lim_{x \to 2}\rm  \frac{(x - 2)(x + 2)[ \sqrt{3x - 2} +  \sqrt{x + 2}]}{3x - 2 - x - 2}

 \rm \:  =  \: \displaystyle\lim_{x \to 2}\rm  \frac{(x - 2)(x + 2)[ \sqrt{3x - 2} +  \sqrt{x + 2}]}{2x - 4}

 \rm \:  =  \: \displaystyle\lim_{x \to 2}\rm  \frac{(x - 2)(x + 2)[ \sqrt{3x - 2} +  \sqrt{x + 2}]}{2(x - 2)}

 \rm \:  =  \: \displaystyle\lim_{x \to 2}\rm  \frac{(x + 2)[ \sqrt{3x - 2} +  \sqrt{x + 2}]}{2}

 \rm \:  =  \:   \dfrac{(2 + 2)[ \sqrt{3(2) - 2} +  \sqrt{2 + 2}]}{2}

 \rm \:  =  \:   \dfrac{(4)[ \sqrt{6 - 2} +  \sqrt{4}]}{2}

 \rm \:  =  \: 2( \sqrt{4} + 2)

 \rm \:  =  \: 2(2 + 2)

 \rm \:  =  \: 8

Hence,

\sf\implies \: \boxed{\tt{ \:\displaystyle\lim_{x \to 2}\rm  \frac{ {x}^{2}  - 4}{ \sqrt{3x - 2}  -  \sqrt{x + 2} } = 8 \: }}

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Answered by MysticSohamS
3

Answer:

your solution is in above pics

pls mark it as brainliest

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