当n为偶数f(x)=sin(nπ-x)cos(nπ+x)/cos((n+1)π-x)*tan(x-nπ)*cot(nπ/2+x)=sin(-x)cosx/[-cos(-x)]tanxcotx=sinx=sinπ/6=1/2当n为奇数f(x)=sin(nπ-x)cos(nπ+x)/cos((n+1)π-x)*tan(x-nπ)*cot(nπ/2+x)=[-sin...