What we do Today! a. Pick up your last week work and mark it (5 min) b. You will receive 3 samples, mark them, and give feedbacks: rank them (25 min) c. Submit the feedbacks d. Revise and edit your last week work, we mark that one (10 min). e. Teaching: Review and Rational and irrational numbers (15 min). f. On boards: Show that 2, 7/6, 2/12 are rational and 2 1/2 is irrational.
Welcome back to Problems, Conjectures and Proofs (MATH 1200) PR FS
Outline ● Directed Proof ● Contrapositive ● Counterexample (disprove) ● Contradiction ● Rational and Irrational Numbers
Directed Proof
Contrapositive
Counterexample (disprove)
Contradiction
Rational and irrational A real number of the form m/n, where m and n are integers and gcd(m,n)=1, is called a rational number . We write Q for the set of all rational number. If a real number is not a rational number, it is a irrational number.
On boards: Show that 2, 7/6, 2/12 are rational and 2 1/2 is irrational.
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