在宇宙空间和世界上,大量存在“不等关系”。这类关系在数学中的表现形式是用符号“>”或“<”连结量与量、量与式、式与式等,统称为“不等式”。下面是中学数学中一些重要的不等式。’ (1)(x_1-x_2)~2≥0及x_1~2+x_2~2≥2x_x_2(其中x_1、x_2>0,当x_1=x_2时,等号成立) (2)(x_1/x_2)+(x_2/x_1)≥2(其中x_1、x_2>0,当x_1=x_2时,等号成立) (3)如果x>0,y>0,xy=1,则x+y≥2(当x=y时,等号成立) 一般说来:如果x_i>0,x_1·x_2…x_n=1(其中i=1,2…n,n表自然数) In space and in the world, there are many “unequal relations.” Such relations in mathematics in the form of the symbol “>” or “ 0, when x_1 = x_2, the equal sign holds) (2) (x_1 / x_2) + (x_1, x_2> 0, equal sign when x_1 = x_2) (3) If x> 0, y> 0 and xy = 1, then x + y≥2 = y, the equals sign holds) Generally speaking: if x_i> 0, x_1 · x_2 ... x_n = 1 (where i = 1, 2 ... n, n is a natural number)