math 2: functions Flashcards
unless explicitly stated, the domain of a function is
all real values that produce real numbers as solutions
in a relation, unlike a function, a particular input number might be paired with
more than one output number
sum function→
(f+g)(x)= f(x) + g(x)
difference function→
(f-g)(x)= f(x) - g(x)
product function→
(f x g)= f(x) x g(x)
quotient function→
(f/g)(x) = f(x)/ g(x); g(x) ≠ 0
composition of functions→
(f ∘ g)(x)= f(g(x))
g ∘ f)(x)= g(f(x)
to confirm if a function is an inverse of another function (rule)
( f^-1 ∘ f)(x) = (f ∘ f^-1)(x) = x
if the inverse of a function is not a function, it can be made into a function by
limiting the domain
since the domains and ranges of inverses are switched, the range of a function can be found by finding the
domain of the inverse
a relation is even if (-x, y) is in the relation whenever
(x, y) is
a relation is odd if (-x, -y) is in the relation whenever
(x, y) is
sum of even functions is
even
sum of odd functions is
odd
product of 2 even or odd functions is
even