Description
Use the method of proof by contradiction.
1. [4 points] Prove that ā6 is irrational.
2. [4 points] If š, š šā¤ , then š) ā 4š ā 2 ā 0.
3. [4 points] Suppose Suppose Aā Ć. Since Ć āAĆA, the set R= Ć is a relation on A. Is R
reflexive? Symmetric? Transitive? If a property does not hold, say why.
4. [4 points] Define a relation R on Z as xRy if and only if 4 | (x + 3y)
Prove R is an equivalence relation.
Describe its equivalence classes.



