Practice Composition Chains in Math

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

Quick Recap

A composition chain is a sequence of functions applied one after another: (f∘g∘h)(x)=f(g(h(x))), evaluated inside-out from right to left.

Work from the innermost function outward — compute h(x) first, then feed that result to g, then feed that to f. The order matters critically.

Showing a random 20 of 50 problems.

Example 1

easy
Let f(x)=2x+1 and g(x)=x−4. Write the formula for (g∘f)(x).

Example 2

easy
If f(x)=2x and g(x)=x+3, write the formula for f(g(x)).

Example 3

easy
Given f(x)=3x−1 and g(x)=x2, find (f∘g)(x) and evaluate it at x=2.

Example 4

medium
Given f(x)=x+2, find (f∘f)(x).

Example 5

hard
Decompose H(x)=sin⁡(ex2) as a composition H=f∘g∘h of three simpler functions.

Example 6

challenge
Given f(x)=x+a and g(x)=bx, find conditions on a and b so that f∘g=g∘f for all x.

Example 7

hard
If f(x)=1/x for x≠0, find (f∘f)(x).

Example 8

easy
For f(x)=x+3 and g(x)=4x, find g(f(2)).

Example 9

medium
With f(x)=x+1 applied repeatedly, find (f∘f∘f)(x) (apply f three times).

Example 10

easy
Let f(x)=x+1, g(x)=2x, h(x)=x2. Compute (f∘g∘h)(3) step by step.

Example 11

medium
If f(x)=x2 and g(x)=3x+1, find (f∘g)(x) and (g∘f)(x) as formulas.

Example 12

challenge
Decompose H(x)=(2x+5)3+1 into a chain f(g(h(x))) of three simple functions and identify the application order.

Example 13

easy
If f(x)=2x and g(x)=x+3, write the formula for g(f(x)) and note it differs from f(g(x)).

Example 14

easy
If f(x)=x+4 and g(x)=x−4, find (f∘g)(x).

Example 15

hard
Let f(x)=x+a and g(x)=bx. Find a and b so that (f∘g)(x)=2x+5 and (g∘f)(x)=2x+10.

Example 16

easy
Let f(x)=x2 and g(x)=x+1. Find (g∘f)(3).

Example 17

medium
Let f(x)=2x−1 and g(x)=(x+1)/2. Compute (f∘g)(x) and (g∘f)(x).

Example 18

medium
Let f(x)=x2−1 and g(x)=x+1. Find (f∘g)(x) and state where it is defined.

Example 19

medium
Functions: h(x)=x2, g(x)=x+1, f(x)=3x. Compute (f∘g∘h)(2).

Example 20

easy
For f(x)=3x and g(x)=x−6, write the formula for f(g(x)).