Math Problem Statement

Functions [f] (solid) and [g] (dashed) are graphed. Two congruent cubic graphs labeled f and g on an x y coordinate plane. The x- and y- axes scale by two. The graph labeled f has point at (negative two, negative two). It increases from left to right and is concave down from the interval of negative five to negative two and is concave up from the interval negative two to two. The graph labeled g has point at (negative two, two). It decreases from left to right and is concave up from the interval of negative five to negative two and is concave down from the interval negative two to two. [\small{2}] [\small{4}] [\small{6}] [\small{8}] [\small{\llap{-}2}] [\small{\llap{-}4}] [\small{\llap{-}6}] [\small{\llap{-}8}] [\small{2}] [\small{4}] [\small{6}] [\small{8}] [\small{\llap{-}2}] [\small{\llap{-}4}] [\small{\llap{-}6}] [\small{\llap{-}8}] [y] [x] [\blueD f] [\maroonD g] [f] is defined as

[f(x)=\dfrac{1}4(x+2)^3-2]. What is the equation of [g]?

Solution

The graphs of ff and gg appear to be transformations of each other. To determine the equation of g(x)g(x), let’s analyze the relationship between f(x)f(x) and g(x)g(x):

  1. The function f(x)f(x) is given by: f(x)=14(x+2)32f(x) = \frac{1}{4}(x + 2)^3 - 2

  2. Observing the graph:

    • The graph of g(x)g(x) appears to be a reflection of f(x)f(x) over the xx-axis.
    • A reflection over the xx-axis changes the sign of the output of f(x)f(x), giving g(x)=f(x)g(x) = -f(x).
  3. Applying the reflection: Substituting f(x)f(x) into g(x)g(x), we have: g(x)=f(x)=(14(x+2)32)g(x) = -f(x) = -\left(\frac{1}{4}(x + 2)^3 - 2\right)

  4. Simplify: Distribute the negative sign: g(x)=14(x+2)3+2g(x) = -\frac{1}{4}(x + 2)^3 + 2

Thus, the equation of g(x)g(x) is: g(x)=14(x+2)3+2g(x) = -\frac{1}{4}(x + 2)^3 + 2

Summary:

The equation of g(x)g(x) is: g(x)=14(x+2)3+2g(x) = -\frac{1}{4}(x + 2)^3 + 2

Would you like me to plot or verify this result?

Relative Questions:

  1. How do reflections over the xx- and yy-axes affect equations of functions?
  2. What other transformations could make g(x)g(x) from f(x)f(x)?
  3. How does the vertex of f(x)f(x) and g(x)g(x) relate geometrically?
  4. Can g(x)g(x) be represented as a shifted version of another cubic function?
  5. How would g(x)g(x) behave if reflected again?

Tip:

When reflecting a graph over the xx-axis, negate the entire function f(x)f(x).

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Math Problem Analysis

Mathematical Concepts

Cubic Functions
Reflections
Transformations

Formulas

f(x) = (1/4)(x + 2)^3 - 2
g(x) = -f(x)

Theorems

Reflection over the x-axis negates the function's output

Suitable Grade Level

Grades 9-12