Functions and Their Properties

This video tutorial introduces the concept of functions, using a practical example of pizza sales to explain how functions work. It covers the definition, properties, domain, and range of functions, and demonstrates how to graph them on a coordinate plane. The tutorial also explores how to analyze graphs to determine if points belong to a function and discusses the behavior of functions, including increasing and decreasing trends. The video concludes with a summary of the key points covered.

What is the profit when 50 pizzas are sold?

• 750,000 VND

• 1,500,000 VND

• 500,000 VND

• 1,000,000 VND

Which of the following is NOT a function?

• y = 1 + 2x

• y^2 = 1 + x

• y = x^3 + 2x

• y = sqrt(2 - x)

What is the domain of the function y = sqrt(2 - x)?

• x < 2

• x > 2

• x ≥ 2

• x ≤ 2

How many values of y correspond to each value of x in a function?

• None

• Three

• One

• Two

Which point lies on the graph of y = x + 3?

• (0, 0)

• (1, 2)

• (-1, 2)

• (0, 3)

What is the y-intercept of the function y = -x + 1?

• (0, 0)

• (1, 0)

• (0, 1)

• (1, 1)

Which of the following points does NOT lie on the graph of y = x^2?

• (0, 0)

• (2, 4)

• (1, 1)

• (-1, 0)

What is the value of f(-2) for the function y = x^2?

• 4

• 2

• 0

• -4

On which interval is the function y = 2x^2 increasing?

• (-∞, 0)

• (0, ∞)

• (-∞, ∞)

• (0, 1)

How is a decreasing function represented on a graph?

• A vertical line

• A horizontal line

• A line going down from left to right

• A line going up from left to right