Example 4
daniel's cell phone company offers a flat-rate unlimited texting plan for $25 per month. daniel's cost
per text in a given month depends on the number of texts he sent and received that month, according
to the function f(x) shown in the table. use the table to find and interpret the value of f-'(0.05).
25
50
100
150
200
300
400
500
750
1,000
1.00
0.50
0.25
0.17
0.13
0.08
0.06
0.05
0.03
0.03