1)

  The domain of the function 

$f(x)= \frac{1}{\sqrt{[x]^{2}-[x]^{}-2}}$  is 

 Here [x]  denotes the greatest integer not exceeding the value of [x]


A) $(-\infty,-2)\cup (1, \infty)$

B) $(-\infty,-2)\cup (0, \infty)$

C) $(-\infty,-2)\cup (2, \infty)$

D) $(-\infty,-1)\cup (3, \infty)$

Answer:

Option D

Explanation:

We have, 

$f(x)= \frac{1}{\sqrt{[x]^{2}-[x]^{}-2}}$ 

 f(x0 is defined when 

$[x]^{2}-[x]-2 >0$

$([x]-2)([x]+1)>0$

 [x] >2 and [x] <-1

 $x\geq 3 $and x<-1

 $\therefore$   Domain of f(x)  is  x $\in $$(-\infty,-1)\cup (3, \infty)$