Practice Function Families in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A function family is a group of functions sharing the same general form and behavior, differing only in the values of one or more parameters.

y=mx+b is a family of lines. Different m and b give different lines.

Showing a random 20 of 50 problems.

Example 1

medium
Two parabolas are y=x2 and y=−2x2. Name their shared family and two ways the parameter changes the graph.

Example 2

hard
Classify y=e−x2 — is it linear, polynomial, exponential, or something else?

Example 3

challenge
A family is defined by f(x)=ax2 with a≠0. Prove that every member passes through the origin and explain why varying a cannot change that.

Example 4

easy
In y=ax2+bx+c, what role does a play (besides being a parameter)?

Example 5

medium
A table shows f(1)=2, f(2)=5, f(3)=10, f(4)=17. Identify the family.

Example 6

medium
What family is y=x3 (cube root)?

Example 7

hard
A linear and an exponential function both pass through (0,5) and (1,10). Find each. At x=4, which is larger?

Example 8

challenge
A mystery function has these values: f(1)=2, f(2)=6, f(3)=18, f(4)=54. Identify the family and the specific member.

Example 9

hard
For the family y=asin⁡(bx)+c, which parameter changes the vertical midline?

Example 10

hard
The family y=xn for integer n≥1 has different behavior depending on whether n is even or odd. Classify and explain the symmetry of y=x2, y=x3, y=x4, y=x5.

Example 11

medium
Classify y=4x versus y=x4 by family, and state which grows faster for large x.

Example 12

medium
The family y=kx (with k≠0). Describe the role of k on the graph.

Example 13

medium
Which family does y=5sin⁡(2x) belong to?

Example 14

medium
Two members of the linear family pass through given points: line A has slope 2, line B has slope 2 but a different intercept. What is true about their graphs?

Example 15

easy
Is y=1x in the same family as y=x2?

Example 16

easy
Classify y=−4x+1 by family.

Example 17

medium
A function doubles every time x increases by 1, and equals 5 at x=0. Identify its family and write the specific member.

Example 18

easy
In the family y=a(x−h)2+k, which parameter shifts the vertex horizontally?

Example 19

hard
A radioactive sample has half-life 5 years. Identify the family and write a model starting from 80 g.

Example 20

medium
A line and a parabola both pass through (0,0) and (2,4). Identify each by family.