Proof Flashcards
What are natural numbers
1,2,3…
What are integers
Whole numbers
how can rational numbers be represented
a number that can be represented as the quotient p/q of two integers such that q ≠ 0
p/q is in it’s simplest form and
both p and q cannot be even
What are real numbers
Any number including irational numbers
What letter are natural numbers represented by
N
What letter are integers represented by
Z
, what letter are rational numbers represented by
Q
What letter are real numbers
R
Disprove by counterexample
To disprove a conjecture all you need is to find a single instance where the injector is not true. this is called a counterexample
Deduction
Direct proof, or proof by deduction is used when you need to show that a situation is true for all possible sets of numbers (when there are too many to test, i.e. infinitely many). In this case the proof consists of a set of logical steps providing a logical argument as to why the congestion must be true, and usually involves algebra (n)
Exhaustion
Proof by exhaustion is used where there are a limited number of possibilities which can all be tested
All integers can be written in three ways =
3k
3k-1
3k-2
because the three times table includes 3, 6
the missing numbers are a vaslue of 3 minus one and a value of three minus 2`