Math Problem Statement

solve with steps

The user submitted multiple questions involving functions, inverses, and composite functions, asking for step-by-step solutions.

Solution

Let's go through each question step-by-step.


Question 1

  1. (a) Find f1(x)f^{-1}(x): We need to find the inverse of f(x)f(x).

    Given: f(x)=3x1f(x) = 3x - 1

    1. Set f(x)=yf(x) = y: y=3x1y = 3x - 1
    2. Solve for xx: y+1=3xy + 1 = 3x x=y+13x = \frac{y + 1}{3}
    3. Replace yy with xx in the expression: f1(x)=x+13f^{-1}(x) = \frac{x + 1}{3}
  2. (b) Calculate f1(x)f^{-1}(x): We already found f1(x)=x+13f^{-1}(x) = \frac{x + 1}{3}.


Question 2

  1. (a) Calculate the value of f(g(2))f(g(2)): Given f(x)=3x1f(x) = 3x - 1 and g(x)=2x+4g(x) = 2x + 4.

    1. First, find g(2)g(2): g(2)=2(2)+4=4+4=8g(2) = 2(2) + 4 = 4 + 4 = 8
    2. Now, find f(g(2))=f(8)f(g(2)) = f(8): f(8)=3(8)1=241=23f(8) = 3(8) - 1 = 24 - 1 = 23

    So, f(g(2))=23f(g(2)) = 23.

  2. (b) Calculate the value of f(f(3))f(f(3)):

    1. First, find f(3)f(3): f(3)=3(3)1=91=8f(3) = 3(3) - 1 = 9 - 1 = 8
    2. Now, find f(f(3))=f(8)f(f(3)) = f(8) (we already calculated this in part (a)): f(8)=23f(8) = 23

    So, f(f(3))=23f(f(3)) = 23.

  3. (c) Find gf(x)gf(x):

    Here, gf(x)=g(f(x))gf(x) = g(f(x)).

    1. Start with f(x)=3x1f(x) = 3x - 1.
    2. Substitute f(x)f(x) into g(x)g(x): g(f(x))=g(3x1)=2(3x1)+4g(f(x)) = g(3x - 1) = 2(3x - 1) + 4
    3. Simplify: =6x2+4=6x+2= 6x - 2 + 4 = 6x + 2

    So, gf(x)=6x+2gf(x) = 6x + 2.


Question 3

  1. (a) Find f(g(x))f(g(x)): Given f(x)=x23f(x) = x^2 - 3, g(x)=2x+1g(x) = 2x + 1, and h(x)=x2h(x) = \frac{x}{2}.

    1. Substitute g(x)g(x) into f(x)f(x): f(g(x))=f(2x+1)=(2x+1)23f(g(x)) = f(2x + 1) = (2x + 1)^2 - 3
    2. Expand: =4x2+4x+13=4x2+4x2= 4x^2 + 4x + 1 - 3 = 4x^2 + 4x - 2

    So, f(g(x))=4x2+4x2f(g(x)) = 4x^2 + 4x - 2.

  2. (b) Find g(h(x))g(h(x)):

    1. Substitute h(x)h(x) into g(x)g(x): g(h(x))=g(x2)=2(x2)+1g(h(x)) = g\left(\frac{x}{2}\right) = 2\left(\frac{x}{2}\right) + 1
    2. Simplify: =x+1= x + 1

    So, g(h(x))=x+1g(h(x)) = x + 1.

  3. (c) Find h1(x)h^{-1}(x):

    1. Start with h(x)=x2h(x) = \frac{x}{2}.
    2. Set h(x)=yh(x) = y: y=x2y = \frac{x}{2}.
    3. Solve for xx: x=2yx = 2y
    4. Replace yy with xx: h1(x)=2xh^{-1}(x) = 2x

Question 4

  1. (a) Solve f(x)=17f(x) = 17:

    Given f(x)=4x7f(x) = 4x - 7.

    1. Set f(x)=17f(x) = 17: 4x7=174x - 7 = 17
    2. Add 7 to both sides: 4x=244x = 24
    3. Divide by 4: x=6x = 6

    So, x=6x = 6 when f(x)=17f(x) = 17.


Would you like further explanation on any specific part? Here are some related questions you might consider exploring:

  1. How can we verify if two functions are inverses of each other?
  2. What is the difference between composite functions like f(g(x))f(g(x)) and g(f(x))g(f(x))?
  3. How do we find the inverse of a quadratic function?
  4. How can we solve equations with more than one function involved?
  5. What are some real-life applications of composite and inverse functions?

Tip: When calculating f(g(x))f(g(x)) or g(f(x))g(f(x)), always simplify your result as much as possible to avoid complex expressions.

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Math Problem Analysis

Mathematical Concepts

Functions
Composite Functions
Inverse Functions
Algebra

Formulas

Function composition: f(g(x))
Inverse function: f(f^{-1}(x)) = x

Theorems

Inverse Function Theorem

Suitable Grade Level

Grades 10-12