voi a,b,c,d, la cac so duong thoa man a*b = c*d =1 chung minh bat dang thuc : ( a+b )*( c+d ) +4 >= 2*( a+b+c+d ) cac ban oi giup minh voi OK
Voi a,b,c la cac so duong thoa man a*b =c*d =1 chung minh (a+b)(c+d) + 4>= 2(a+b+c+d)
1. Cho a,b,c,d la cac so nguyen thoa man \(a^2=b^2+c^2+d^2\)
chung minh rang a.b.c.d + 2015 viet duoc duoi dang hieu cua 2 so chinh phuong.
2. Cho a,b la cac so duong thoa man dieu kien a+b=1. tim gia tri nho nhat cua bieu thuc
\(P=\frac{2+a}{\sqrt{2-a}}+\frac{2+b}{\sqrt{2-b}}\)
cho a,b,c la cac so duong thoa man (1/a+1/b+1/c)>=(a+b+c), chung minh a+b+c>=3abc
cho cac so thuc a,b,c la cac so thuc thoa man a+1/b=b+1/c=c+1/a CMR a=b=c
a,Tim cac so a,b sao cho |2x+a| = |bx+5| voi moi x\(\in\)R
b,Cho a,b,c,d,e,f la cac so thuc thoa man: |ax+b| + |cx+d| = |ex+f| voi x\(\in\)R.
Biet a,c,e \(\ne\)0. C/m: ad=bc
cho a,b,c la cac so thuc duong thoa man 21ab+2bc+8ac <= 12
khi do gia ti nho nhat cua A=1/a+2/b +3/c
a,b,c la cac so thuc duong thoa man \(\frac{1}{1+a}+\frac{1}{1+b}+\frac{1}{1+c}=2\)
Max P=abc
cho a,b,c la cac so thuc duong thoa man a+b+c=3. tim gia tri nho nhat cua
P=\(\frac{a}{a^3+b^2+c}+\frac{b}{b^3+c^2+a}+\frac{c}{c^3+a^2+b}\)