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Find F (0), So that F ( X ) = X 1 − √ 1 − X Becomes Continuous at X = 0. - Mathematics

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Question

Find f (0), so that  \[f\left( x \right) = \frac{x}{1 - \sqrt{1 - x}}\]  becomes continuous at x = 0.

 

Sum
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Solution

if \[f\left( x \right)\]is continuous at x = 0, then  
\[\lim_{x \to 0} f\left( x \right) = f\left( 0 \right)\]       ...(1)

Given:

\[f\left( x \right) = \frac{x}{1 - \sqrt{1 - x}}\]

\[\Rightarrow f\left( x \right) = \frac{x\left( 1 + \sqrt{1 - x} \right)}{\left( 1 - \sqrt{1 - x} \right)\left( 1 + \sqrt{1 - x} \right)}\]
\[ \Rightarrow f\left( x \right) = \frac{x\left( 1 + \sqrt{1 - x} \right)}{1 - \left( 1 - x \right)}\]
\[ \Rightarrow f\left( x \right) = \left( 1 + \sqrt{1 - x} \right)\]

\[\lim_{x \to 0} \left( 1 + \sqrt{1 - x} \right) = f\left( 0 \right) \left[ \text{ From eq}  . (1) \right]\]
\[\Rightarrow f\left( 0 \right) = 2\]

So, for 

\[f\left( 0 \right) = 2\], the function f(x) becomes continuous at x = 0.
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Chapter 9: Continuity - Exercise 9.3 [Page 41]

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RD Sharma Mathematics [English] Class 12
Chapter 9 Continuity
Exercise 9.3 | Q 3 | Page 41

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