Book: RS Aggarwal - Mathematics
Chapter: 3. Functions
Subject: Maths - Class 11th
Q. No. 6 of Exercise 3C
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Find the domain and the range of each of the following real function: 
Given: 
Need to find: Where the functions are defined.
To find the domain of the function f(x) we need to equate the denominator of the function to 0.
Therefore,
x – 4 = 0
⇒ x = 4
It means that the denominator is zero when x = 4
So, the domain of the function is the set of all the real numbers except 4.
The domain of the function, Df(x) = (- ∞, 4) ∪ (4, ∞).
Now if we put any value of x from the domain set the output value will be either (-ve) or (+ve), but the value will never be 8
So, the range of the function is the set of all the real numbers except 8.
The range of the function, Rf(x) = (-∞, 8) ∪(8, ∞).
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