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Need solution for RD Sharma maths class 12 chapter Continuity exercise 8.2 question 18

Answers (1)

Answer:

 x=-2, -5/2

Hint:

 f \circ f(x)=f(f(x))

Given:

 f(x)=1 / x+2

Explanation:

Clearly,

f(x)=1 / x+2

is discontinuous at

X = -2

Also, it is not defined at x = -2

For x ≠ -2  

\begin{aligned} &f(x)=f\left(\frac{1}{x+2}\right) \\ &=\frac{1}{\frac{1}{x+2}+2} \\ &=\frac{\frac{1}{2 x+5}}{x+2} \\ &=\frac{x+2}{2 x+5} \end{aligned}

We observe that,

f(f(x))  is discontinuous and not defined a

\begin{aligned} x=-\frac{5}{2} \end{aligned}

Hence

f(f(x)) is not continuous at x = -2 and

\begin{aligned} x=-\frac{5}{2} \end{aligned}

Posted by

Gurleen Kaur

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