Production by Mr Porter 2009 Revision - Surds 1 2 Production by Mr Porter 2009
Definition : If p and q are two integers with no common factors and , than a is an irrational number. Irrational number of the form are called SURDS. 1 2
Surd Operations If a, b, c and d are numbers and a > 0 and b > 0, then Surds can behave like numbers and/or algebra.
Simplifying Surds To simplify a surd expression, we need to (if possible) write the given surd number as a product a perfect square, n2, and another factor. It is important to use the highest perfect square factor but not essential. If the highest perfect square factor is not used first off, then the process needs to be repeated (sometimes it faster to use a smaller factor). Generate the perfect square number: Order 1 2 3 4 5 6 7 8 9 10 n2 12 22 32 42 52 62 72 82 92 102 Value 16 25 36 49 64 81 100 Perfect Squares Factorise the surd number using the largest perfect square : 18 = 9 x 2 24 = 4 x 6 27 = 9 x 3 48 = 16 x 3 Or any square factor: 72 = 36 x 2 72 = 9 x 8 72 = 4 x 18 72 = 4 x 9 x 2
Examples: Simplify the following surds. 1 4 9 16 25 36 49 64 81 100 121 144 169 196 225
Exercise: Simplify each of the following surds. 1 4 9 16 25 36 49 64 81 100 121 144 169 196 225
Simplifying Surd Expressions. Examples: Simplify the following (simplify each surd part first). N2 1 4 9 16 25 36 49 64 81 100 121 144 169 196 225
Exercise: Simplify the following. 1 4 9 16 25 36 49 64 81 100 121 144 169 196 225
Simplifying Surd Expressions. Examples: Simplify the following
Exercise: Simplify each of the following (fraction must have a rational denominator).
Using the Distributive Law - Expanding Brackets. Examples: Expand and simplify the following
Exercise: Expand the following (and simplify) Special cases - (Product of conjugates) Difference of two squares.
Rationalising the Denominator - Using Conjugate Examples: In each of the following, express with a rational denominator. [more examples next slide]
More examples
Exercise: Express the following fraction with a rational denominator. Harder Type questions. Express the following as a single fraction with a rational denominator. Example A possible method to solve this problems is to RATIONALISE the denominators of each fraction first, then combine the results.
Exercise: Express the following as a single fraction with a rational denominator.