先求导数y'=5/(2*根号x)设切点坐标为(a,5根号a)切线方程为y=kx+b代入切点和P的坐标得b=55根号a=ak+bk=(5根号a-5)/a由导数可知k=5/(2*根号a)5/(2*根号a)=(5根号a-5)/a5a=10a-10根号aa-2根号a=02根号a=aa^2-4a=0a=0或a...