Math Problem Statement

Let P(x, y) be the statement “x 2 + y 2 = 2024.” If the domain for both variables consists of all real numbers, what are the truth values? (a) ∃x P(x, √ 2024) (b) ∀x ∃y P(x, y) (c) ∃x ∃y P(x, y) (d) ∀x ∃y P(x, y)

Solution

Let's analyze the truth values of the statements involving P(x,y)P(x, y), where P(x,y)P(x, y) is defined as x2+y2=2024x^2 + y^2 = 2024, and the domain for both variables consists of all real numbers.

(a) xP(x,2024)\exists x \, P(x, \sqrt{2024})

This statement means "There exists an xx such that x2+(2024)2=2024x^2 + (\sqrt{2024})^2 = 2024." Since (2024)2=2024(\sqrt{2024})^2 = 2024, this simplifies to: x2+2024=2024x^2 + 2024 = 2024 x2=0x^2 = 0 Thus, x=0x = 0 is the only solution. Therefore, there exists such an xx, so the statement is true.

(b) xyP(x,y)\forall x \, \exists y \, P(x, y)

This statement means "For all xx, there exists a yy such that x2+y2=2024x^2 + y^2 = 2024."

Rearranging, we need y2=2024x2y^2 = 2024 - x^2. This requires that 2024x202024 - x^2 \geq 0, i.e., x22024x^2 \leq 2024, which is always true for all real xx because for any real number, we can find a corresponding yy such that y2=2024x2y^2 = 2024 - x^2. Hence, the statement is true.

(c) xyP(x,y)\exists x \, \exists y \, P(x, y)

This statement means "There exists an xx and a yy such that x2+y2=2024x^2 + y^2 = 2024."

For example, if x=0x = 0 and y=2024y = \sqrt{2024}, then 02+(2024)2=20240^2 + (\sqrt{2024})^2 = 2024. Therefore, the statement is true.

(d) xyP(x,y)\forall x \, \exists y \, P(x, y)

This is the same as statement (b). It means "For all xx, there exists a yy such that x2+y2=2024x^2 + y^2 = 2024." As shown in the analysis for (b), this is true.

Summary of truth values:

  • (a) True
  • (b) True
  • (c) True
  • (d) True

Would you like more details or have any questions?

Here are 5 related questions to explore:

  1. What is the geometric interpretation of P(x,y)P(x, y)?
  2. How would the truth values change if the domain were restricted to integers?
  3. Can you generalize these statements for x2+y2=r2x^2 + y^2 = r^2?
  4. What is the set of all points (x,y)(x, y) that satisfy x2+y2=2024x^2 + y^2 = 2024?
  5. How does the solution change if P(x,y)=x2+y22024P(x, y) = x^2 + y^2 \geq 2024?

Tip: When working with statements like \exists (there exists) and \forall (for all), always carefully consider the domain of the variables involved.

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Math Problem Analysis

Mathematical Concepts

Algebra
Equations of Circles
Quantifiers (∀, ∃)
Geometry

Formulas

x^2 + y^2 = r^2

Theorems

Geometric Interpretation of Circle Equations
Properties of Quantifiers (Existential and Universal)

Suitable Grade Level

Grades 10-12