to expand a bracket you multiply everything inside the bracket by what is outside
multiplying out a bracket is called factorising
putting in a bracket is called factorising
PLACE VALUE
multiply= left/ divide= right
SQUARES AND CUBES
square- the result of multiplying a whole number by itself
4 x 4 (the square of 4) =16
SQUARE ROOTS AND CUBE ROOTS
square roots- a number which when multiplied by itself gives you the its root
cube roots- a number which when multiplied by itself, then multiplied by itself again
cube- comes from multiplying a number by itself and then multiplying the result by the original number
4 x 4 x 4 (4 cubed) = 64
PERCENTAGE CHANGE
RATIO
ratios are used to compare quantities
they can be simplified like fractions
to do so you divide each of its numbers by a common factor
GRAPHS
gradient
lines that slant upwards have a positive gradient
lines that slant downwards have a negative gradient
midpoint
is halfway along the line
to find it: (+ x-coordinates, ÷ by 2 and + the y-coordinates and ÷ by 2
across= x, upwards= y
SHAPES
circles
circumference= outside (perimeter)
diameter= middle
radius= a section of the line across the middle (diameter)
(Area= 3.142squared) A=πr2
prisms
volume= area of cross section x length
pythagoras
a2+ b2 = c2
c2= n, n√
rectangle
perimeter= l + w + l + w
area= l x w
square
area= a measure of the amount of space within a shape e.g- a 1cm by 1cm square is 1cm2
area= l x l
parallelogram area= base x height
triangle area= 1/2 x b x h
trapezium area = 1/2 (a + b lengths of parallel sides) x h
LOCI
CONSTRUCTIONS
perpendicular bisector of a line segment
the locus of a point which moves so that it's an equal distance from two points (A&B) is the perpendicular bisector of the line joining A and B
perpendicular= at right angles to
bisector= cut in half
BISECTING AN ANGLE
after drawing an angle at the corner labelled V would be the angle to bisect
placing your compass on V, draw an arc that crosses both sides of the angle
label those points A and B
place your compass on point A and draw an arc between the two sides of the angle
then, without moving the compass place it on point B and draw another arc that cuts through the previous, label this C
draw a straight line through point V to C
the line VC bisects the angle
to do so you draw a line segment XY (the numbers at either end)
put you compass on X, set halfway along the line, then draw an arc proceed to do the same from the opposite end close to Y but halfway along (they should cross)
label the two points A and B, draw a straight line through A and B where lines X and Y , A and B cross within the middle of the arcs, along the right angle label M ad draw a box
the point M where the lines cross is the midpoint of XY and AB is perpendicular to XY
the locus of a point moves so that it is always a set distance from a fixed point
the locus of a point moves so that it is a set distance from the line between points P and Q which will be at opposite ends of said line
after measuring a set distance from the line to the measurement provided using a compass you should draw around the line
CORRELATION
correlation is positive when the values increase together
correlation is negative when one value decreases as the other increases
0 is no correlation (the values will appear to not link at all)
-1 is a perfect negative correlation
the value shows how good the correlation is not how steep the line is and if it is positive or negative
1 is a perfect correlation
PIE CHARTS
when given survey results that may be presented in a table to show this within a pie chart with the numbers still in a table you then divide each value by the total and multiply by 100 to get a percentage