rxcr.net
当前位置:首页 >> 设函数y Cos x 求Dy >>

设函数y Cos x 求Dy

设函数y=cosx,求dy.因为y=cosx所以dy/dx=2cosx(-sinx)=-sin2x因此:dy=-sin2xdx

y=x^3cosxdy/dx=3x^2cosx+x^3*(-sinx)dy=(3x^2cosx-x^3sinx)dx

-sin(x+y)(1+y`)+1=0sin(x+y)(1+y`)=11+y`=1/sin(x+y)=csc(x+y)y`=csc(x+y)-1

dy/dx=d(cos(x))=-sin(x)

[1+sin(x+y)]=-sin(x+y) y'=-sin(x+y)/[1+sin(x+y)] 所以dy=-sin(x+y)/y'=-(x+y)'sin(x+y)=-(1+y')sin(x+y) 得y'

dy=d[cos2x/(x-1)]=y'dx={[-2sin2x*(x-1)-cos2x]/(x-1)^2}dx=-[2sin2x*(x-1)+cos2x]/(x-1)^2 dx

解:dy/dx=[cos(x-1)]'=-sin(x-1)(x-1)'=sin(1-x)2x=2xsin(1-x)dy=2xsin(1-x)dx

两边同时对x求导,得:y求导得dy/dxcos(x+y)求导得sin(x+y)*(1+dy/dx)右边求导为0.把这些带入上式就有方程dy/dx+sin(x+y)*(1+dy/dx)=0解方程后应该是dy=sin(x+y)dx/(1+sin(x+y))

-2sinxcosx,你的意识就是(cosx)的平方,2可以写到cos和x中间的,然后就是这个结果.

网站首页 | 网站地图
All rights reserved Powered by www.rxcr.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com