(1)B/A+A/B大于等于2(2)(庚號(hào)AB)小于等于(A+B)/2小于等于[庚號(hào)(A^2+B^2)/2](3)(4A/A)+A^2小于等于1

熱心網(wǎng)友

b/a+a/b≥2,b/a=a/b,a=b時(shí)取等號(hào)√ab≤(a+b)/2≤√(a^2+b^2)/2,a=b時(shí)取等號(hào)因?yàn)閍+b≥2√ab,(a-b)^2≥0,a=b時(shí)取等號(hào)(把不等式化簡(jiǎn)即可(4a/(a^2+4)≤1,4a≤a^2+4,a^2-4a+4≥0,(a-2)^2≥0,a=2取等號(hào).