The number of real solutions for equation (x2006+1)(1+x2+x4+⋯+x2004)=2006x2005 is .
Solution
We have ⇔⇔⇔(x2006+1)(1+x2+x4+⋯+x2004)=2006x2005(x+x20051)(1+x2+x4+⋯+x2004)=2006x+x3+x5+⋯+x2005+x20051+x20031+x20011+⋯+x1=20062006=x+x1+x3+x31+⋯+x2005+x20051≥2×1003=2006, where the equal holds if and only if x=x1, x3=x31, ..., x2005=x20051. Then x=±1. Since x≤0 does not satisfy the original equation, x=1 is the only solution. So the number of real solutions is 1.
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