Express the following functions as set of ordered pairs and determine their range.
f: X → R, f (x) = x3 + 1, where X = {–1, 0, 3, 9, 7}
According to the question,
A function f: X →R, f (x) = x3 + 1, where X = {–1, 0, 3, 9, 7}
Domain = f is a function such that the first elements of all the ordered pair belong to the set X = {–1, 0, 3, 9, 7}.
The second element of all the ordered pair are such that they satisfy the condition f (x) = x3 + 1
When x = – 1,
f (x) = x3 + 1
f (– 1) = (– 1)3 + 1 = – 1 + 1 = 0 ⇒ ordered pair = (–1, 0)
When x = 0,
f (x) = x3 + 1
f (0) = (0)3 + 1 = 0 + 1 = 1⇒ ordered pair = (0, 1)
When x = 3,
f (x) = x3 + 1
f (3) = (3)3 + 1 = 27 + 1 = 28⇒ ordered pair = (3, 28)
When x = 9,
f (x) = x3 + 1
f (9) = (9)3 + 1 = 729 + 1 = 730⇒ ordered pair = (9, 730)
When x = 7,
f (x) = x3 + 1
f (7) = (7)3 + 1 = 343 + 1 = 344⇒ ordered pair = (7, 344)
Therefore, the given function as a set of ordered pairs is
f = {(–1, 0), (0, 1), (3, 28), (7, 344), (9, 730)}
And,
Range of f = {0, 1, 28, 730, 344}