Math Problem Statement

If  f(x) = x+4  and  g(x) = 2x2-x-1, evaluate the composition (g o f)(2).

Solution

To solve the composition (gf)(2)(g \circ f)(2), we first need to find the value of f(2)f(2) and then use this result to evaluate g(f(2))g(f(2)).

Step 1: Find f(2)f(2)

The function f(x)=x+4f(x) = x + 4.

f(2)=2+4=6f(2) = 2 + 4 = 6

Step 2: Evaluate g(f(2))=g(6)g(f(2)) = g(6)

Now we need to find g(6)g(6) using the function g(x)=2x2x1g(x) = 2x^2 - x - 1.

g(6)=2(6)261g(6) = 2(6)^2 - 6 - 1

Calculate 626^2:

62=366^2 = 36

Substitute back into the equation:

g(6)=2(36)61=7261=65g(6) = 2(36) - 6 - 1 = 72 - 6 - 1 = 65

Final Answer

(gf)(2)=g(f(2))=g(6)=65(g \circ f)(2) = g(f(2)) = g(6) = 65

So, the value of the composition (gf)(2)(g \circ f)(2) is 65.


Would you like to explore any further details, or have any other questions?

Here are some related questions:

  1. What is the definition of a function composition?
  2. How

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra
Quadratic Functions

Formulas

f(x) = x + 4
g(x) = 2x^2 - x - 1
(g o f)(x) = g(f(x))

Theorems

Composition of Functions

Suitable Grade Level

Grades 9-10