不等式：修订间差异
来自高中笔记
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<math>\frac {b}{a} - \frac {b + c}{a + c} = \frac {ab + bc - ab - ac}{a(a + c)} = \frac {bc - ac}{a(a + c)} = \frac {c(b - a)}{a(a + c)} < 0</math> | <math>\frac {b}{a} - \frac {b + c}{a + c} = \frac {ab + bc - ab - ac}{a(a + c)} = \frac {bc - ac}{a(a + c)} = \frac {c(b - a)}{a(a + c)} < 0</math> | ||
所以 <math>\frac { | 所以 <math>\frac {b}{a} < \frac {b + c}{a + c}</math>. | ||
= 例题 = | = 例题 = | ||