Given f(x) = 2x + 3 and g(x) = x^2 - 1, find (f ∘ g)(x).
Solution
Problem
Given f(x) = 2x + 3 and g(x) = x^2 - 1, find (f ∘ g)(x).
Step 1: Recall the meaning of function composition.
The notation (f ∘ g)(x) means:
f(g(x))
This tells us to apply g first and then use its output as the input of f.
Step 2: Write the two functions.
f(x) = 2x + 3
g(x) = x^2 - 1
Step 3: Substitute g(x) into f.
Since f(x) = 2x + 3, replace x in f with x^2 - 1:
f(g(x)) = 2(x^2 - 1) + 3
Step 4: Distribute the 2.
f(g(x)) = 2x^2 - 2 + 3
Step 5: Combine like terms.
f(g(x)) = 2x^2 + 1
Therefore:
(f ∘ g)(x) = 2x^2 + 1.
Result
(f ∘ g)(x) = 2x^2 + 1