NextstopISB
I. \(f(x) = √(\frac{x}{100})^2\)
II. \(f(x) = [square_root][25x]\)
III. \(f(x) = \frac{(x^2-32)}{((x-5) (x + 5))}\)
Which of the above functions has as its domain the set of all real numbers?
a) I only
b) III only
c) I and II only
d) I and III only
e) I II and III
CONCEPT:
1) A value becomes non-real if the value is NEGATIVE INSIDE SQUARE ROOT, such as √(-3) is non-real
2) Also, a function is NOT DEFINED when the denominator becomes zero such as 1/(x-2) is not defined for x = 2
I. \(f(x) = √(\frac{x}{100})^2\)
This function is valid for positive as well as Negative values of x as squaring the negative value results in a positive value under the square root.
hence, it is
DEFINED for all Real values of x
II. \(f(x) = √[25x]\)
this function will result in a non-real value for any negative value of x hence it is
NOT DEFINED for all real values of x
III. \(f(x) = \frac{(x^2-32)}{((x-5) (x + 5))}\)
This is
not defined for x = 5 and x=-5 for which the denominator becomes zero
Hence, Answer: Option A
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