判断f(x)=[1/(2^x-1)+1/2]x奇偶性,

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判断f(x)=[1/(2^x-1)+1/2]x奇偶性,
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判断f(x)=[1/(2^x-1)+1/2]x奇偶性,
判断f(x)=[1/(2^x-1)+1/2]x奇偶性,

判断f(x)=[1/(2^x-1)+1/2]x奇偶性,
f(x) = [1/(2^x-1)+1/2]x
f(-x) =[1/(2^-x -1)+1/2](-x)
= [2^x / (1- 2^x) +1/2](-x)
= [2^x /(2^x -1) - 1/2]x
= [2^x /(2^x -1) -1 +1/2]x
=[2^x /(2^x -1) - (2^x -1)/(2^x -1) +1/2]x
=[1/(2^x -1) +1/2]x
=f(x)
故f(x)是偶函数.

做这类题的思路,可以先用-x替换x,即写出f(-x),然后直奔f(x)或-f(x)而去。如果f(-x)既不等于f(x)也不等于-f(x),则这个函数是非奇非偶。