Question

导数微分,在的数字是平方,立方1.求曲线y=xlnx-x在x=e处的切线方程2.设Y=4X-5cos+e+ln5,求dy

Answer 1

1.y'=lnx+x*1/x-1=lnx,k=lne=1,切线方程为：y=x-e

2.y'=12x^2+5sinx+e^x,dy=(12x^2+5sinx+e^x)dx

3.y'=(e^x)cosx-(e^x)sinx

4.dy=y'dx=[cos(x^2-1)]*2xdx=2xcos(x^2-1)dx

5.lny=x+y,lny-y=lnx ,y'/y-1=1/x ,y'= (1+1/x)y