17/07/17 13:05:29.18 2cOdQU+V.net
>>136
(1) (a+b)^2 = 4ab + (a-b)^2 ≧ 4ab ≧ 4^2
(2) y ≧ xx + 4/x^8 = 4/x^3 + (x - 2/x^4)^2 ≧ 4/x^3,
x(x+y) ≧ x(x + 4/x^3) = xx + 4/xx = 4 + (x - 2/x)^2 ≧ 4,
17/07/17 13:05:29.18 2cOdQU+V.net
>>136
(1) (a+b)^2 = 4ab + (a-b)^2 ≧ 4ab ≧ 4^2
(2) y ≧ xx + 4/x^8 = 4/x^3 + (x - 2/x^4)^2 ≧ 4/x^3,
x(x+y) ≧ x(x + 4/x^3) = xx + 4/xx = 4 + (x - 2/x)^2 ≧ 4,