Cho a+b+c>3. CMR a^4+b^4+c^4>=a^3+b^3+c^3
Cho a,b,c>0;a+b+c=3.cmr : a^3+b^3+c^3/a^4+b^4+c^4<hoac=1
Cho a,b,c>0. CMR \(\frac{a^4}{a^3+b^3}+\frac{b^4}{b^3+c^3}+\frac{c^4}{c^3+a^3}\ge\frac{a+b+c}{2}\)
Cho a+b+c=0, cm a)a^3+b^3+c^3=3abc
b) a^2+b^2+c^2=2(a^4+b^4+c^4)
Cho a,b,c>0
a+b+c=3
CMR:
Giúp mình với pls
Cho a+b+c=3
CMR: \(a^4+b^4+c^4\ge a^3+b^3+c^3\)
a) Cho a3+b3+c3-3abc . CMR: a+b+c=0 ; a=b=c.
b) Cho a4+b4+c4+d4=4abcd và a,b,c,d >0 . CMR : a=b=c=d.
cho a,b,c,d > 0. CMR \(\frac{a^4}{a^3+2b^3}+\frac{b^4}{b^3+2c^3}+\frac{c^4}{c^3+2d^3}+\frac{d^4}{d^3+2a^3}\ge\frac{a+b+c+d}{3}\)
Phân tích thành nhân tử
1, a(b-c)3+b(c- a)3+c(a- b)
2, a^4(b-c)+b^4(c-a)+c^4(a-b)
3, bc(a+d)(b-c)-ac(b+d)(a-c)+ab(c+d)(a-b)
4, (a+b+c)^3-(a+b-c)^3-(b+c-a)^3-(c+a-b)^3
5, (b-c)^3+(c-a)^3+(a-b)^3