Question

Angelica is shopping for a new cell phone plan. she wants a cell phone plan that will cover unlimited calling texting and up to 4gb of data. she finds a plan defined by the function f(x)=9.99x + 120 where x represents the additional gb of data. $9.99 is the cost of the additional data, $120 is the cost of the cell phone plan up to 4gb and c(x) is the total cost. What is the domain of the function?

Answer 1

The domain of a function are the possible x values.

Given the function: f(x) = 9.99x + 120 where x represents the additional gb of data.

Thus, the domain of the function are the possible additional gb of data which can be represented by numbers from 0 and above.

Therefore, the domain of the function is the positive real numbers.

Answer 2

The domain of a function refers to the possible values of x for which the function is valid. In this question, x is the number of additional gb of data, of which Angelica only wants up for 4 gb. Assuming only integers values of gb are acceptable, the domain of the function c(x) is the set {0, 1, 2, 3, 4}.