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In the Following, Determine the Value of Constant Involved in the Definition So that the Given Function is Continuou: \[F\Left( X \Right) = \Begin{Cases}Kx + 5, and \Text{ If } X \Leq 2 \\ X - 1, - Mathematics

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Question

In the following, determine the value of constant involved in the definition so that the given function is continuou: \[f\left( x \right) = \begin{cases}kx + 5, & \text{ if  }  x \leq 2 \\ x - 1, & \text{ if }  x > 2\end{cases}\]

Sum
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Solution

Given: 

\[f\left( x \right) = \begin{cases}kx + 5, & \text{ if  }  x \leq 2 \\ x - 1, & \text{ if }  x > 2\end{cases}\]
If  \[f\left( x \right)\] is continuous at x = 2, then 
\[\lim_{x \to 2^-} f\left( x \right) = \lim_{x \to 2^+} f\left( x \right)\]
\[\Rightarrow \lim_{h \to 0} f\left( 2 - h \right) = \lim_{h \to 0} f\left( 2 + h \right)\]
\[ \Rightarrow \lim_{h \to 0} \left( k\left( 2 - h \right) + 5 \right) = \lim_{h \to 0} \left( 2 + h - 1 \right)\]
\[ \Rightarrow 2k + 5 = 1\]
\[ \Rightarrow 2k = - 4\]
\[ \Rightarrow k = - 2\]
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Chapter 9: Continuity - Exercise 9.2 [Page 35]

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RD Sharma Mathematics [English] Class 12
Chapter 9 Continuity
Exercise 9.2 | Q 4.2 | Page 35

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