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Indices. Chapter 1 2014 – Year 10 Mathematical Methods. Review of Index Laws. Some numbers can be written in mathematical shorthand if the number is the product of "repeating numbers”. Example : a 7 = a × a × a × a × a × a × a = aaaaaaa Index and base form 64 = 2 6
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Indices Chapter 1 2014 – Year 10 Mathematical Methods
Review of Index Laws Some numbers can be written in mathematical shorthand if the number is the product of "repeating numbers”. Example: a7= a × a × a × a × a × a × a = aaaaaaa Index and base form 64 = 26 • The 10 is called the index number • The 2 is called the base number The plural of “index” is “indices” Another name for index form is power form or power notation 26 is read as: two to the power of 6
Review of Index Laws Index Law 2 26 24 In general terms am an Index Law 1 23 x 25 = 23+5 = 28 In general terms am x an = am+n Index Law 3 23 23 In general terms a0 = 1 = 23-3 =20 = 1 = 26-4 =22 = am-n
Review of Index Laws Index Law 4 (24)2 = 24 X 2 = 28 In general terms (am)n = am x n = amn Index Law 6 In general terms Index Law 5 (2 x 3)4 = 23 x 34 In general terms (a x b)m = am x bm
Examples Solve: m2n6p2 x m3np4 = m2+3n6+1p2+4 = m5n7p6 Solve: 6x3y5 2xy2 =3x3-1y5-2 =3x2y3
Examples Which of the following is equivalent to (x½)6? A. x6½ B. x3 C.6x½ D. ½x6 We get: = x½x 6 = x3 B Using law 4 (am)n = am x n = amn
Examples Which of the following is equivalent to (2y⅔)3? A. 8y2 B. 2y2 C.8y3 D. 2y3 Using law 4 (am)n = am x n = amn We get: = 23y⅔ x 3 = 8y2 A
Negative Indices Lets have a look at this example of Index Law 2 y2y x y1 y4 y x y x y x yy2 Therefore we know y-2 also can be written as Seventh Index Law a-n = It can also be written as =y-2 or 1 y2 1 an
Negative Indices • All index laws apply to terms with negative indices • Always express answers with positive indices unless otherwise instructed • Numbers and pronumerals without an index are understood to have an index of 1 e.g. 2 = 21
Examples Write the numerical value of: Express the following with a positive index:
Examples • Simplify these algebraic expression: HINT – remove the brackets first, then use the index laws and then express with positive indices.
Fractional Indices • Fractional indicesarethosewhichareexpressedasfractions.
Combining Index Laws When more than one index law is used to simplify an expression, the following steps can be taken. Step 1: If an expression contains brackets, expand them first. Step 2: If an expression is a fraction, simplify each numerator and denominator, then divide (simplify across then down). Step 3: Express the final answer with positive indices.
Combining Index Laws Simplify :
Combining Index Laws Simplify:
Combining Index Laws Simplify:
Combining Index Laws Simplify:
Combining Index Laws Simplify:
Combining Index Laws Simplify:
Combining Index Laws • Simplification of expressionswithindicesofteninvolvesapplicationofmorethanoneIndex law. • If anexpressioncontainsbrackets, theyshouldberemovedfirst. • If theexpressioncontainsfractions, simplifyacrossthendown. • Whendividingfractions, change÷ to × and flipthesecondfraction(multiply and flip). • Expressthefinal answerwithpositive indices.