f(x)=[a(2^x+1)-2]/(2^x+1)=a-2/(2^x+1)
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æ以-2/(2^x+1)æ¯å¢å½æ°
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ç±f(-x)=-f(x)å¾å°ï¼
(a•2^(-x)+a-2)/(2^(-x)+1)= - (a•2^x+a-2)/(2^x+1);
ç±äº2^(-x)=1/2^x, æ以ï¼
[a+(a-2)•2^x]/ï¼2^x+1ï¼=- (a•2^x+a-2)/(2^x+1);
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a+(a-2)•2^x =- (a•2^x+a-2)ï¼
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a-2=-a, æ以a=1ï¼
f(x)=[a(2^x+1)-2]/(2^x+1)=a-2/(2^x+1)
å 为2^x+1æ¯å¢å½æ°
æ以2/(2^x+1)æ¯åå½æ°
æ以-2/(2^x+1)æ¯å¢å½æ°
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2.ï¼2ï¼ æ以f(x)=(2^x-1)/ (2^x+1);ç±äºå¯¹xâRï¼2^x>0,
对äºy>0ï¼f(y)=(y-1)/(y+1)= (y+1-2)/(y+1)=1-2/(y+1);
f(y)å¨y>0æ¶éå¢,æ以ï¼è2x为xçéå¢å½æ°ï¼æ以f(x)为éå¢å½æ°ï¼
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