Page 11 - 數學B學習講義含解析

Chapter 1 坐標系與函數圖形 5

重點 三 實數的運算

1. ண aebec މ΂จྼᅰdۆ

Ȅ ɧɓܛj˜a > bea = bea < b™ɧόʕܦ̥Ϟɓࡈึϓͭf

ȅ ჈୅ܛjǺ߰ a > b ˲ b > cdۆ a > c

ǻ߰ a = b ˲ b = cdۆ a = c

Ǽ߰ a < b ˲ b < cdۆ a < c

Ȇ ഃඎʮଣjǺ߰ a = bdۆ a + c = b + c

ǻ߰ a = bdۆ a - c = b - c

Ǽ߰ a = bdۆ a $ c = b $ c

ǽ߰ a = bdۆ a ÷ c = b ÷ c(c ! 0)

ȇ ʔഃඎʮଣjǺ߰ a > bdۆ a + c > b + c

ǻ߰ a > bdۆ a - c > b - c

c > 0 & ac > bc
Ǽ߰ a > bd˲ )
c < 0 & ac < bc
a b
c > 0 & >
c
ǽ߰ a > bd˲ * c b
a
c < 0 & <
c c
2
2
2. ̻˙ڢࠋ׌j࿁΂จٙྼᅰ adۆ a $ 0d˲ a = 0 ̥ί a = 0 ࣛϓͭf