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Define f(x) as the product of two real functions f_1(1)=x, x \in IR and f_z(x)=\left\{\begin{array}{c}\sin \frac{1}{x}, \text { if } x=0 \\ 0, \text { if } x=0\end{array}\right. as follows f(x)=\left\{\begin{array}{r} f_1(x) \cdot f_2(x), \text { If } x \neq 0 \\ 0, \text { if } x=0 \end{array}\right. 
Statement I: f(x) is continuous on IR.
Statement II : f_1(x) and f_2(x) are continuous on IR.

Option: 1

Statement I is false, statement II is true.


Option: 2

Statement I is true, statement II is true. Statement II is a correct explanation of statement I.


Option: 3

Statement I is true, statement II is true. Statement II is not a correct explanation of statement I


Option: 4

Statement I is true, statement II is false. 


Answers (1)

best_answer

f(x)= \begin{cases}\sin \frac{1}{x}, & x \neq 0 \\ 0 & , x=0\end{cases}
To, check continuity at x=0,
$$ \underset{x\rightarrow 0^{+}}{lim} f(x)=0=\underset{x\rightarrow 0^{-}}{lim} f(x)=f(0)
So, continuous.
Statement I is correct.
\begin{aligned} f_2(x) & = \begin{cases}\sin \frac{1}{x}, & x \neq 0 \\ 0 & , x=0\end{cases} \\ \lim _{x \rightarrow 0} f_2(x) & =\lim _{x \rightarrow 0} \sin \left(\frac{1}{x}\right) \end{aligned}
it does not exist. 

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Kuldeep Maurya

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