Math Problem Statement
Which of the following statements are true? Select all that apply. Assume the domain of discourse is the set of real numbers.
A.
∃x such that x2=x+1
B.
∀x,x2≤x
C.
∀x,x2=0
D.
∃x such that x2≤x
Solution
Let's analyze each statement:
A. ∃x such that x² = x + 1
This asks if there exists a real number such that . Rearrange the equation: The discriminant () is: Since , this quadratic equation has two real solutions. Therefore, this statement is true.
B. ∀x, x² ≤ x
This asks if for all real numbers , . Rearrange: The critical points are and . Test intervals:
- For : (false).
- For : (true).
- For : (false).
Thus, this statement is false because it is not true for all .
C. ∀x, x² = 0
This asks if for all real numbers , . Clearly, this is false because is only true when . For other values of , .
D. ∃x such that x² ≤ x
This asks if there exists a real number such that . From the analysis in :
- is true for .
- For example, satisfies .
Thus, this statement is true.
Final Answer:
- True: A, D
- False: B, C
Would you like further details or a graph to visualize these solutions?
Here are some related questions you might find interesting:
- How do we solve quadratic inequalities like ?
- What is the significance of the discriminant () in quadratic equations?
- Can hold for all and ?
- What are the differences between "for all" () and "there exists" ()?
- How can graphing help verify solutions to these types of problems?
Tip: When dealing with inequalities, always analyze the critical points and test intervals.
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Math Problem Analysis
Mathematical Concepts
Real Numbers
Quadratic Equations
Inequalities
Existential Quantifiers
Universal Quantifiers
Formulas
Quadratic equation: ax² + bx + c = 0
Discriminant formula: Δ = b² - 4ac
Inequality analysis: x(x - 1) ≤ 0
Theorems
Properties of quadratic equations
Solution of inequalities with critical points
Suitable Grade Level
Grades 10-12
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