Section 2 Flashcards
Meaning of if a then b
If a is true then b is true. If a is false then b can be either true or false
a only if b
can only be false if a is true and b is false. logically equivalent to if a then b
a if and only if b
the same thing as[ (if a then b) and (if b then a) ] b and a can only be true in the same circumstances and false in the same circumstances
a if b
logically equivalent to if b then a
converse
swaps a and b. a statement and its converse are only equivalent in the case of a iff b
contrapositive
a and b are swapped and negated. statement and contrapositive are equivalent in the case of a only if b
a is necessary for b
if a is necessary for b then if b then a is true. when b is true then a is true and if a is false then b is false aswell. if b is false then a could be true or false
a is sufficient for b
a is sufficient for b means the same thing as if a then b, so if a is true then b is true but if a is false b can be true or false.
convex graph
fââ(x)>0
Root of a^2 equals
mod a not a