Lesson 3 - Brackets and Rationalising Denominators.pptx

Maths SURDS Concept

1. Skills Pack – Surds Lesson 3: Brackets and Rationalising Denominators Cambridge IGCSE ™ Version 0.1

2. More Operations with Surds Now we need to incorporate surds with the other operations we can do with algebra. Things such as adding and subtracting surds, expanding brackets with surds in, and dividing by surds.

3. Adding/Subtracting Surds My turn:   In general:                 Collect the terms like algebra. Cannot be simplified any further

4. Adding/Subtracting Surds Your turn:                

5. Surds in Brackets My turn:     Multiply out brackets how you normally would with algebra.          

6. Surds in Brackets My turn:        

7. Surds in Brackets Your turn:            

8. Rationalising a denominator My turn:   Look at the following: We prefer to not have a surd in the denominator, as these are hard to deal with! Instead, we can multiply the top and bottom by another surd to make the denominator an integer (which is a rational number)     Why? Multiplying a surd by itself will leave no surd in the denominator. And the value of the fraction in the box is ‘1’, so it doesn’t change the value of the original fraction.  

9. Rationalising a denominator My turn:                    

10. Rationalising a denominator My turn:         No need to multiply by the ‘3’ too.

11. Rationalising a denominator Your turn:              

12. Now work through Worksheet 3