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落叶船
等下,还在写呢,有点复杂,慢慢看。嗯 好就采纳呗
a+b+c=0
两边平方得a^2+b^2+c^2+2ab+2bc+2ca=0
移项得a^2+b^2+c^2=-2ab-2bc-2ca
再两边平方得a^4+b^4+c^4+2a^2b^2+2b^2c^2+2c^2a^2
=4a^2b^2+4b^2c^2+4c^2a^2+4ab^2c+4abc^2+4a^2bc
=4a^2b^2+4b^2c^2+4c^2a^2+4abc(b+a+c)
=4a^2b^2+4b^2c^2+4c^2a^2+4abc×0
=4a^2b^2+4b^2c^2+4c^2a^2
所以a^4+b^4+c^4=4a^2b^2+4b^2c^2+4c^2a^2-(2a^2b^2+2b^2c^2+2c^2a^2)
即a^4+b^4+c^4=2a^2b^2+2b^2c^2+2c^2a^2