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a(2n-1)x^(2n-1)+a(2n-2)x^(2n-2)+â¦â¦+a2x^2+a1x+a0=0
å
¶ä¸æé«æ¬¡é¡¹ç³»æ°a(2n-1)â 0
令f(x)=a(2n-1)x^(2n-1)+a(2n-2)x^(2n-2)+â¦â¦+a2x^2+a1x+a0
å¦æa(2n-1)>0,åå½x->+âæ¶,f(x)->+âï¼
å½x->-âæ¶,f(x)->-â.
å f(x)å¨xâRä¸è¿ç»,æ ¹æ®ä»å¼å®ç,å¿
æä¸å®æ ¹x0满足f(x0)=0.
å¦æa(2n-1)
+âæ¶,f(x)->-âï¼
å½x->-âæ¶,f(x)->+â.
å f(x)å¨xâRä¸è¿ç»,æ ¹æ®ä»å¼å®ç,å¿
æä¸å®æ ¹x0满足f(x0)=0.
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