F.3 數學(指數定律)

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2^2n x 4^n+4
=2^2n x 2^2n+4 <---(2GE2次係4..so..4=2^2...4^n=2^2n)
=2^4n+4 <-----(定義:當2個底係一樣ge時候,可x入去....要指數相+)
=2^4n+2^2
=2^4n+2

16^n x 8^-2
=16^n x (1除8^2)<----係1除(8^2) 定義:當'指數係負ge話要分母轉分子.
分子轉分母親(唔明add我)
16^n
= ____
64

2008-09-11 21:06:18 補充：
ANS 係 (16^n)/64.....打錯野 Sor

2^2nx4^n+4
=2^2nx4^nx4^4
=2^2nx4^nx256
=(2^2)^nx4^nx256
=4^nx4^nx256

16^n x 8^-2
=16^n /8^2/1

Let 2^n = u.
Then 2^2n = u^2.
4^(n + 4) = 2^[2(n + 4)] = 2^(2n + 8) = u^2 . 2^8 = 256u^2.
16^n = 2^4n = u^4
1/8^(-2) = 8^2 = 64.
So the expression = (u^2)(256u^2)(64)/u^4 = 16384.