讨论函数f(x)=x/x2+1的单调性和奇偶性.

问题描述:

讨论函数f(x)=x/x2+1的单调性和奇偶性.
解到[X1X2(X2-X1)+(X1-X2)]不知道怎么判断了

f(-x) = -x/[(-x)²+1] = -x/(x²+1) = -f(x)此函数是奇函数 设 x1 < x2f(x1) - f(x2)= x1/(x1²+1) - x2/(x2²+1)= [x1(x2²+1)-x2(x1²+1)] / [(x1²+1)(x2²+1)]= [x1x...增减性写反了,请自己更正