CMR so thuc a,b,c thi a^2+b^2+c^2+ab+bc+ca  lon hon hoac bang  0

CMR so thuc a,b,c thi a^2+b^2+c^2+ab+bc+ca  lon hon hoac bang  0

cho a,b,c la ba so duong . CMR:a/b+c + b/a+c + c/a+b lon hon hoac bang 3/2

Bai 2: cho a,b,c>0.CMR

\(\frac{a^3}{bc}+\frac{b^3}{ac}+\frac{c^3}{ab}\)lon hon hoac bang  a+b+c

goi a,b,c la cac canh cua 1 tam giac co 3 duong cao tuong ung la ha,hb,hc. cmr (a+b+c)^2/ha^2+hb^2+hc^2 lon hon hoac bang 4

cho a,b,c>1.cmr \(\frac{a^2}{b-1}\)+\(\frac{b^2}{c-1}\)+\(\frac{c^2}{a-1}\)lon hon hoac bang 12

c/m voi 3 so thuc tuy y ta co

a² cong b² cong 1 lon hon hoac bang ab cong a cong b

cho cac so thuc duong thoa man a+b+c=3.cmr:

(a²+ab²/b²+a+b)+(b²+bc²/c²+b+c)+(c²+ca²/a²+c+a) lon hon hoac bang 2

1.     cho 4 stn a lon hon hoac bang b, b lon hon hoac bang c, clon hon hoac bang d.

CM:(a-b)(a-c)(a-d)(b-c)(b-d)(c-d)

2.      CM: co the tim dc 1 stn k sao cho: (1997^k)-1 chia het cho 10^4

3.      tong cac chu so cua 1 so chinh phuong co the bang 1995 dc k?

4.      tong cua 1995 stn khac 0 dung bang 1995. Hoi UCLN cua chung la bao nhieu?