A5xy20的精选

问题详情：曲线y=-5ex+3在点(0,-2)处的切线方程为()A.5x+y+2=0          B.5x-y+2=0C.x+5y+2=0          D.x-5y+2=0【回答】A.因为y′=-5ex,y′|x=0=-5,即在点(0,-2)处的切线斜率为-5,所以切线方...