Math Problem Statement

Giải và vẽ

Sketch the graph and find the domain and range of each function: (a) f(x) = 2x - 1, (b) f(x) = x^2

Solution

Let's analyze and solve the problem step-by-step.

Problem (from the image):

You are asked to sketch the graph and find the domain and range of each of the following functions:

  1. f(x)=2x1f(x) = 2x - 1
  2. f(x)=x2f(x) = x^2

(a) f(x)=2x1f(x) = 2x - 1

1. Graph:

  • This is a linear function, where the slope is 22 and the y-intercept is 1-1.
  • The line passes through the points:
    • x=0x = 0: f(0)=1f(0) = -1 (so the line crosses the y-axis at (0,1)(0, -1)).
    • x=1x = 1: f(1)=2(1)1=1f(1) = 2(1) - 1 = 1 (so the line passes through (1,1)(1, 1)).

The graph is a straight line with slope 2, slanting upwards from left to right.

2. Domain:

  • The domain of any linear function is all real numbers.
  • Domain: (,)(-\infty, \infty)

3. Range:

  • Since the function is linear and continuous without any restrictions, the range also includes all real numbers.
  • Range: (,)(-\infty, \infty)

(b) f(x)=x2f(x) = x^2

1. Graph:

  • This is a parabola that opens upwards.
  • It has a vertex at (0,0)(0, 0), and it is symmetric about the y-axis.
  • The parabola passes through:
    • (1,1)(1, 1) because f(1)=12=1f(1) = 1^2 = 1.
    • (1,1)(-1, 1) because f(1)=(1)2=1f(-1) = (-1)^2 = 1.
    • As x|x| increases, the function values f(x)=x2f(x) = x^2 also increase.

The graph of this function is a U-shaped curve opening upwards.

2. Domain:

  • The function f(x)=x2f(x) = x^2 is defined for all real values of xx.
  • Domain: (,)(-\infty, \infty)

3. Range:

  • Since the function is a parabola that opens upwards, the lowest value of f(x)f(x) is 0 (at x=0x = 0), and it increases as xx moves away from 0.
  • Range: [0,)[0, \infty)

Summary:

  • (a) f(x)=2x1f(x) = 2x - 1:

    • Domain: (,)(-\infty, \infty)
    • Range: (,)(-\infty, \infty)
  • (b) f(x)=x2f(x) = x^2:

    • Domain: (,)(-\infty, \infty)
    • Range: [0,)[0, \infty)

Would you like me to provide a detailed graph for both functions?

Here are 5 related questions to expand your understanding:

  1. How does the slope of a linear function affect the steepness of the graph?
  2. What happens to the graph of f(x)=x2f(x) = x^2 if you add or subtract a constant (e.g., f(x)=x2+1f(x) = x^2 + 1)?
  3. How would the graph of f(x)=2x1f(x) = 2x - 1 change if the slope is negative?
  4. Can you find the x-intercept of f(x)=2x1f(x) = 2x - 1 and explain its significance?
  5. How do you determine the vertex of a quadratic function like f(x)=x2+4x+3f(x) = x^2 + 4x + 3?

Tip:

When analyzing the domain and range, always check for restrictions on the inputs (e.g., square roots or denominators) to make sure the function is defined for all values.

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Math Problem Analysis

Mathematical Concepts

Linear Functions
Quadratic Functions

Formulas

f(x) = 2x - 1
f(x) = x^2

Theorems

Slope-Intercept Form
Parabola Vertex

Suitable Grade Level

Grades 8-10