函数y=2/(tanx-cotx)的图像的对称轴

设对称轴坐标为(t,0),则
2/(tan(x-t)-cot(x-t))=2/(tan(2t-x)-cot(2t-x));
tan(x-t)-cot(x-t)=tan(2t-x)-cot(2t-x);
tan(2t-x)-tan(x-t)=cot(2t-x)-cot(x-t);
右=[tan(x-t)-tan(2t-x)]/[tan(x-t)·tan(2t-x)];
则tan(2t-x)-tan(x-t)=[tan(x-t)-tan(2t-x)]/[tan(x-t)·tan(2t-x)];
tan(x-t)·tan(2t-x)=-1;
tan(x-t)·tan(x-2t)=1;
[(tanx-tant)/(1+tanx·tant)][(tanx-tan2t)/(1+tanx·tan2t)]=1;
(tanx)^2-(tant+tan2t)tanx+tant·tan2t=1+tanx·(tant+tan2t)+(tanx)^2·tant·tan2t
(tanx)^2·(1-tant·tan2t)-2tanx·(tant+tan2t)=1-tant·tan2t;
[1-(tanx)^2]·(1-tant·tan2t)+2tanx·(tant+tan2t)=0;
[1-(tanx)^2]·{1-tant·2tant/[1-(tant)^2]}+2tanx·[tant+2tant/(1-(tant)^2]=0;