Let f : R → R : f(x) = x2. Determine
(i) range (f)
(ii) {x : f(x) = 4}

• Range(f):

For finding the range of the given function, let y = f(x) Therefore,

y = x2 x = √y

The value of y ≥ 0. Hence, Range(f) is [0, ∞).

• Let y = f(x) = Given y = 4.

Therefore,

=4 x = 2 or x = -2

The set of values for which y = 4 is x = {2,-2}.