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Lim X → a X − a √ X − √ a

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Question

\[\lim_{x \to a} \frac{x - a}{\sqrt{x} - \sqrt{a}}\]

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Solution

\[\lim_{x \to a} \left[ \frac{x - a}{\sqrt{x} - \sqrt{a}} \right]\] 

=  \[\lim_{x \to a} \left[ \frac{\left( \sqrt{x} \right)^2 - a^2}{\sqrt{x} - \sqrt{a}} \right]\] 

=  \[\lim_{x \to a} \left[ \frac{\left( \sqrt{x} - \sqrt{a} \right) \left( \sqrt{x} + \sqrt{a} \right)}{\left( \sqrt{x} - \sqrt{a} \right)} \right]\] 

=  \[\sqrt{a} + \sqrt{a}\] 

=  \[2\sqrt{a}\]

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Chapter 29: Limits - Exercise 29.4 [Page 29]

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R.D. Sharma Mathematics [English] Class 11
Chapter 29 Limits
Exercise 29.4 | Q 24 | Page 29

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