quadratics Flashcards
(11 cards)
when solving factorised quadratics consider the…
possibilities
algebraic proof of minima and maxima
- complete the square
- write that (x+a)^2>0
so (x+a)^2 +1>1
therefore the quadratic will always be greater than 1
how to complete the square
half the x coefficient and place this in a bracket with x. square the bracket. work out how much you would have to add or take away. combine this with the number on the outside.
heading for graph sketch
shape, vertex, x ints, y ints
intersection of quadratic with straight line
substitute to find point of intersection
what is the discriminant
b squared minus four a c
solve a quadratic inequality
find critical values
draw a graph
find what you need to
if discriminant is less than zero
no real roots
if discriminant equals zero
one real root, tangent
if discriminant is greater than zero
2 real distinct roots
what is the factor theorem
if f(x) is a polynomial and f(p)=0 then (x-p) is a factor of f(x)