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你好
解:平方后相减得,
ma+nb-(m^2)*a-(n^2)*b-2*m*n*[(ab)^(1/2)]
=(m-m^2)*a+(n-n^2)*b-2mn*[(ab)^(1/2)]
我们知道,
(m-m^2)*a+(n-n^2)*b
>=2*[(m-m^2)^(1/2)]*[(n-n^2)^(1/2)]*(ab)^(1/2)
可以验证:[(m-m^2)^(1/2)]*[(n-n^2)^(1/2)]=mn
所以,
ma+nb-(m^2)*a-(n^2)*b-2*m*n*[(ab)^(1/2)]
=(m-m^2)*a+(n-n^2)*b-2mn*[(ab)^(1/2)]
>=0
所以,(ma+nb)^(1/2)>=m*[a^(1/2)]+n*[b^(1/2)]
如何验证[(m-n^2)^(1/2)]*[(n-n^2)^(1/2)]=mn,劳驾写出步骤。
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