Sec 2 Maths Notes Change Subject
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The document provides examples and techniques for changing the subject of a formula. It demonstrates flipping both sides of an equation, multiplying or dividing both sides by the same term, and isolating the term to be made the subject by collecting like terms on one side of the equation and leaving the term by itself on the other side. Common mistakes discussed include incorrectly flipping terms individually rather than both sides of the equation and prematurely making denominators the same.
Sec 2 Maths Notes Change Subject
- 1. 4048 2EM Algebra – Change Subject (1) Math Academy® All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, or stored in any retrieval system of any nature without prior permission. Math Academy® 1 Knowing is not enough; we must apply. Willing is not enough; we must do. Johann Wolfgang von Goethe Notes: Changing Subject of a Formula Example 1: Make the letter in the brackets the subject of the given formula. Example 2: Example 3: (3 ) 2 w x y c+ = ( )x z yx m = - ( )y 1x y m z - = m x y z - = m x y z - = 2 a b c x = + ( )x 2 1 a b c x + = 2 1x a b c = + 2 a x b c = + 2( ) a x b c = + Common mistake m m z x y - = FLIP EACH side Multiply on both sidesm ALONEy LHS and RHS one term each FLIP EACH side (not flip individually) Multiply on both sidesa Common mistake 1 1 2 x a b c = + LHS: ALONEx Technique: Flip
- 2. 4048 2EM Algebra – Change Subject (1) Math Academy® All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, or stored in any retrieval system of any nature without prior permission. Math Academy® 2 Example 4: Example 5: Example 6: 3 2x y k k y - = ( )x 2 R r T r + = - ( )r 1 11 =+ ba ( )b 1 1 1 b a = - 1 1a b a a = - 1 1a b a - = 1 1 b a a = - 1 a b a = - appears oncex Do not Cross-multiply appears twicer Cross-multiply Group terms with r Cross- Multiply Factorise r Make the term containing on one side.b Make Same Denominator Flip Do not make same denominator at this stage (else appear everywhere --- Tedious !!) b