已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-1)=1两式,求x+y的值.
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已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-1)=1两式,求x+y的值.已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-
已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-1)=1两式,求x+y的值.
已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-1)=1两式,求x+y的值.
已知实数x,y满足(x-1)^3+211(x-1)=-1和(y-1)^3+211(y-1)=1两式,求x+y的值.
将两式相加得
(x-1)^3+(y-1)^3+211(x-1)+211(y-1)=1-1=0
即[(x-1)^3+(y-1)^3]+[211(x-1)+211(y-1)]=0
作因式分解得
(x-1+y-1)[(x-1)^2-(x-1)(y-1)+(y-1)^2]+211(x-1+y-1)=0
即(x+y-2)[(x-1)^2-(x-1)(y-1)+(y-1)^2+211]=0
而f(x)=(x-1)^2-(x-1)(y-1)+(y-1)^2的delta为delta=(y-1)^2-4*(y-1)^2=-3(y-1)^20,f(x)+211>0
因此x+y-2=0
即x+y=2
^是啥意思?
虽然我不会回答。。
但是^什么意思我是知道的!!
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