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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 10: chứng minh: xy/z+yz/x+zx/y>=x+y+z với`x,y,z>0

Toán Lớp 10: chứng minh: xy/z+yz/x+zx/y>=x+y+z vớix,y,z>0

Comments ( 1 )

  1. Theo bất đẳng thức $Cauchy$:
    $⇔  (\frac{xy}{z} +\frac{xz}{y}) +(\frac{yz}{x}+\frac{xy}{z}) +(\frac{xz}{y}+\frac{yz}{x}) ≥ 2x+2y+2z$
    $⇔2.(\frac{xy}{z}+\frac{yz}{x}+\frac{xz}{y}) ≥ 2.(x+y+z)$
    $⇔\frac{xy}{z}+\frac{yz}{x}+\frac{xz}{y} ≥ x+y+z$ (Điều phải chứng minh).

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222-9+11+12:2*14+14 = ? ( )