Annonymous

Maths Revision
PROBABLILITY
P(A) means the probability that a happens
Eg- ½ a knock of getting heads when you jug a coin
P(A) means the probability that A doesnt happen
Eg- ½ a chance of NOT getting heads when you toss a coin.
(P)=1-P(A)
If two events are reciprocally exclusive they cannot both(prenominal) happen at the aforesaid(prenominal) time.
Eg- you cannot get heads and tails both at the homogeneous time.
If events A and B are mutually exclusive then
P(A or B)=P(A)+P(B)
If A and B are nonsymbiotic then…
P(A or B)=P(A)XP(B)

TREE DIAGRAMS.
A box contains 2 black counters and 4 white counters. One counter is picked at random. The tree diagram below shows this.
Black
White

2/6
4/6

cypher the counter is not put back. The contents of the box bequeath be different. If it was black the box would now contain 1 black and 4 white, but if it was white it would have 2 black and 3 white. This is shown below.

WE ALWAYS MULTIPLY ALONG THE BRANCHES AND amplify THE ANSWERS THAT WE NEED.
Questions…
Multiplying out Brackets

(x+2)(x+7)
X²+2x+7x+14
Factorising Quadratic Equations
A quadratic comparability is one that has x ² as a term in it . But no higher powers of x
If necessary re-arrange FIRST.
Eg:
* x(x-5)=2(x+9)
* x²-5x=2x+18
* x²-7x=18
* x²-7x-18=0
then solve the equation.




* Factorise the answer to exact…
(x+2)(x-9)=0
Also notice
(x+8)(x-8)
x²+8x-8x-64
x²-64
So x can be equal to +2 or 9
changing the subject of a formula.
What is the subject?
V=u+at
V would be the subject.
To make u the subject.
V=u+at
flummox at from both sides
v-at=u
Similar shapes
Two shapes are mathematically same if one is an enlargement of the other. Or the angles are the same on both shapes.
Similar Triangles
Two triangles are similar if they…
* Have the same angles as each other
* All pairs of tally sides are in the same ratio
* Two pairs are in the same ratio and the angle between then is the same on both sides
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