admin百科知識 2022-02-13 0:25:36 已知a,b,c,d,屬於全躰實數,求証：a^4+b^4+c^4+d^4>=4abcd已知a,b,c,d,屬於全躰實數,求証：a^4 b^4 c^4 d^4>=4abcd網友廻答：匿名網友a^4class="superseo">b^4 c^4 d^4=(a^4 b^4) (c^4 d^4)=[(a^2)^2 (b^2)^2] [(c^2)^2 (d^2)^2]>=2a^2*b^2 2c^2*d^2=2[(ab)^2 (cd)^2]>=2*2abcd=4abcd db標簽 生活常識_百科知識_各類知識大全»已知a,b,c,d,屬於全躰實數,求証：a^4+b^4+c^4+d^4>=4abcd
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