Cho 0 ≤ a; b; c ≤ 2 0 ≤ a; b; c ≤ 2 thỏa mãn a + b + c = 3a + b + c = 3. Chứng minh rằng: a2 + b2 + c2 ≤ 5a2 + b2 + c2 ≤ 5

B1: Cho 0≤a,b,c≤20≤a,b,c≤2 thỏa mãn a+b+c=3a+b+c=3. CMR: a2+b2+c2≤5a2+b2+c2≤5

B2: Cho a,b≥0a,b≥0 thỏa mãn a2+b2=a+ba2+b2=a+b. TÌm GTLN S=aa+1+bb+1S=aa+1+bb+1

B3: CMR: 1(x−y)2+1x2+1y2≥4xy∀x≠y,xy≠01(x−y)2+1x2+1y2≥4xy∀x≠y,xy≠0