Math Problem Statement

Evaluate the following function compositions and operations based on the given graph of a linear function f and a quadratic function g.

Solution

Let's first analyze the graph to identify the functions ff and gg, and then solve the composition of functions listed.

  • f(x)f(x): The blue linear function. It has a positive slope, and from the graph, we can estimate its equation. The line passes through points like (0,2)(0, -2) and (2,2)(2, 2), so its slope is 2(2)20=2\frac{2 - (-2)}{2 - 0} = 2. Thus, the equation of f(x)f(x) seems to be f(x)=2x2f(x) = 2x - 2.

  • g(x)g(x): The red parabolic function. It appears to have a vertex at (2,4)(2, -4) and opens upwards. The equation might resemble a form of g(x)=a(x2)24g(x) = a(x - 2)^2 - 4. By estimating the value at other points, such as g(0)=0g(0) = 0, we can calculate that g(x)(x2)24g(x) \approx (x - 2)^2 - 4.

Now, let's solve the problems:

  1. (fg)(2)(f \circ g)(2):

    • First, find g(2)g(2). From the graph, g(2)=4g(2) = -4.
    • Now, calculate f(g(2))=f(4)f(g(2)) = f(-4). Using f(x)=2x2f(x) = 2x - 2, f(4)=2(4)2=82=10f(-4) = 2(-4) - 2 = -8 - 2 = -10.
    • Answer: 10-10.
  2. (gf)(2)(g \circ f)(2):

    • First, find f(2)f(2). Using f(x)=2x2f(x) = 2x - 2, f(2)=2(2)2=42=2f(2) = 2(2) - 2 = 4 - 2 = 2.
    • Now, calculate g(f(2))=g(2)g(f(2)) = g(2). From the graph, g(2)=4g(2) = -4.
    • Answer: 4-4.
  3. (ff)(2)(f \circ f)(2):

    • First, find f(2)=2f(2) = 2 (from previous calculation).
    • Now, calculate f(f(2))=f(2)f(f(2)) = f(2). From the previous step, we know f(2)=2f(2) = 2.
    • Answer: 22.
  4. (gg)(2)(g \circ g)(2):

    • First, find g(2)=4g(2) = -4 (from the graph).
    • Now, calculate g(g(2))=g(4)g(g(2)) = g(-4). From the graph, estimate g(4)g(-4). It looks to be around 1212 (as it's far above 10 on the graph).
    • Answer: 1212.
  5. (f+g)(4)(f + g)(4):

    • First, find f(4)f(4). Using f(x)=2x2f(x) = 2x - 2, f(4)=2(4)2=82=6f(4) = 2(4) - 2 = 8 - 2 = 6.
    • Now, find g(4)g(4). From the graph, g(4)=0g(4) = 0.
    • So, f(4)+g(4)=6+0=6f(4) + g(4) = 6 + 0 = 6.
    • Answer: 66.
  6. (fg)(2)\left(\frac{f}{g}\right)(2):

    • We know f(2)=2f(2) = 2 and g(2)=4g(2) = -4.
    • So, f(2)g(2)=24=12\frac{f(2)}{g(2)} = \frac{2}{-4} = -\frac{1}{2}.
    • Answer: 12-\frac{1}{2}.

Would you like further details on any of these steps or explanations?

Here are 5 related questions you could explore:

  1. What is the equation of a parabola given its vertex and one other point?
  2. How do you calculate the composition of two functions in general terms?
  3. How would the answers change if f(x)f(x) had a different slope?
  4. Can you always estimate function values from a graph accurately?
  5. How does the order of composition fgf \circ g differ from gfg \circ f?

Tip: Always check the graph carefully for critical points, such as intercepts and vertices, when identifying function values!

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Math Problem Analysis

Mathematical Concepts

Function Composition
Linear Functions
Quadratic Functions

Formulas

f(x) = 2x - 2 (linear function)
g(x) = (x - 2)^2 - 4 (quadratic function)

Theorems

Composition of Functions: (f ∘ g)(x) = f(g(x))
Basic Function Operations: (f + g)(x), (f / g)(x)

Suitable Grade Level

Grades 9-11