f(x)=tan|x|显然f(-x)=f(x)定义域|x|≠kπ+π/2x≠±(kπ+π/2)也就是x≠kπ+π/2关于原点对称所以是偶函数偶函数,关于y轴对称从图上看出不是周期函数x>0y=tanx则在(kπ-π/2,kπ+π/2)是增函数此时k>=1x<0,y=-tanx则在(kπ-π/2,kπ+π/2)是减函数此时k<=-1k=0,则(-π/2,0)时,y=-tanx,减右半边是增所以kπ-π/2kπ-π/2=1和0