Higher Flashcards
How do you find the equation for a perpendicular bisector
- find gradient of line from co ordinates
- m1m2=-1 (perpendicular)
- find midpoint
- sub points into y=m(x-a)
How do you find the circumcentre
Find the equation for both lines and do simultaneous equations
How do you find the equation of an altitude of a line?
find the gradient of the line that the altitude is perpendicular to
m1m2=-1
sub the point and the gradient into y-b=m(x-a)
How do you find the equation of the median?
- find the midpoint of the side it bisects
- calculate the gradient of the median
- substitute the gradient and either point on the line into y-b=m(x-a)
how do you find the vector journey PQ?
q-p
How do you find the magnitude of a vector AB
square root of a squared + b squared
how do you prove that a vector journey is collinear?
find vector journey A to B
then B to C
if AB=2BC(or anything like that) it means AB is parallel to BC
B is a common point to both AB and BC so A, B and C are collinear
if P is the position vector of the point p that divides AB into the ratio m:n then what is the formula to fine the point p??
p= (x1+x2)/m+n , (y1+y2)/m+n
how do you know if 2 vectors are perpendicular?
a.b=0
how do you find the angle between 2 vectors?
cosx=a.b/(magn a x magn b) = a1b1+a2b2+a3b3/(mag axmag b)
what are the steps for sketching a quadratic function?
- find the shape = the coefficient of x^2
- find y intercept
- find the roots of the equation (factorise and set=0)
- find midway between the roots
- find the coordinates of the TP (complete the square and use a and b)
how do you find the coordinates of the TP of a quadratic
complete the square
y=ax^2+bx+c can be written in the form y=a(x+p)^2+q. so the TP is (-p,q)
how can you solve a quadratic equation?
quadratic equations may be solved by: -the graph -factorising -completing the square - using quadratic formula (find the x's)
how can solve a quadratic inequation?
by sketching the quadratic function
- factorise equation
- find roots by setting factorised equation to 0
- solve for x’s
how do you find the number’ if there are roots
use the discriminant (b^2-4ac)
if b^2-4ac=0 then the roots are real and equal
if b^2-4ac<0 there are no real roots
if b^2-4ac>0 the roots are real and unequal
how can you find unknown coefficients in a quadratic equation?
use the discriminant and solve for the unknown coefficient (e.g p)
how can you determine if a line is a tangent to a curve?
use the discriminant
if the b^2-4ac=0 then there is only one point of intersection
-if b^2-4ac>0 there are 2 distinct points of intersection
-if b^2-4ac<0 the line does not intersect with the curve
how do you find the equation of a tangent
- set the 2 equation equal to eachother and bring both to one side so it =0
- use discriminant to find missing coefficent
- sub number into y=mx+c
how do you find the point of intersection between a curve and a tangent
- set both equations equal to eachother
- use discriminant to find out how many points of intersection
- complete the square/factorise and find coordinates
how do you find the degree of the polynomial?
its the number of the highest power in the equation
how do you know if something is a factor of a polynomial?
if the remainder is 0
how can you factorise a polynomial equation fully
- use synthetic division to fine the factor(s) of the equation
- use the new numbers you found from the synthetic division and put it into brackets along with your factor
- factorise the new equation
how can you find a polynomials coefficient?
- use synthetic division and solve through
- since you know the factor you know the remainder must be 0
- set your last number to 0 and solve for your coefficient (e.g q)
- if you are given more 2 factors or have 2 unknown coefficient then solve through and use simultaneous equations
how can you find the roots of a polynomial equation?
- synthetic division
- factorise fully
- set equal to 0
- solve for x