题目: 函数y=lnx在x=1处的切线方程为( )A.x-y+1=0B.x-y-1=0C.x+y+1=0D.x+y-1=0 答案: ∵y=lnx,∴y′=1x∴函数y=lnx在x=1处的切线斜率为1又∵切点坐标为(1,0)切线方程为y=x-1故选B