- Irrational numbers are numbers that cannot be written as a fraction with the numerator and denominator
as integers. - If thenthroot of a number cannot be simplified to a rational number, it is called a surd.
- Ifaandbare positive whole numbers, anda < b, thenn
p
a <n
p
b.
- A binomial is an expression with two terms.
- The product of two identical binomials is known as the square of the binomial.
- We get the difference of two squares when we multiply(ax+b) (ax b)
- Factorising is the opposite process of expanding the brackets.
- The product of a binomial and a trinomial is:
(A+B) (C+D+E) =A(C+D+E) +B(C+D+E)
- Taking out a common factor is the basic factorisation method.
- We often need to use grouping to factorise polynomials.
- To factorise a quadratic we find the two binomials that were multiplied together to give the quadratic.
- The sum of two cubes can be factorised as:
x^3 +y^3 = (x+y)
(
x^2 xy+y^2
)
- The difference of two cubes can be factorised as:
x^3 y^3 = (x y)
(
x^2 +xy+y^2
)
- We can simplify fractions by incorporating the methods we have learnt to factorise expressions.
- Only factors can be cancelled out in fractions, never terms.
- To add or subtract fractions, the denominators of all the fractions must be the same.
End of chapter Exercise 1 – 11:
1.The figure here shows the Venn diagram for the special setsN;N 0 andZ.
Z
N 0
N
X
a)Where does the number 2,13 belong in the diagram?
b)In the following list, there are two false statements and one true statement. Which of the statements
istrue?
- Every natural number is an integer.
- Every whole number is a natural number.
- There are fractions in the integers.
2.State whether the following numbers are real, non-real or undefined.
a)
p
5 b)
p
8
0
c)
p
15 d)
p
7 e)
p
1 f)
p
2
36 1.9. Chapter summary