Question

高等数学上册习题解答

麻烦你帮我解决这个问题，要具体步骤，谢谢……

Answer 1

d^2y/dx^2=d(dy/dx)/dx=d(-dy/(sintdt))/(-sintdt)=(-(d^2y/dt*sint-dy/dt*cost)/(sint)^2)dt/(-sintdt)=d^2y/dt^2/(sint)^2-dy/dt*cost/(sint)^3
原方程可化为1/(sint)^2*d^2y/dt^2-cost/(sint^3)*dy/dt+cost/(sint)^2*dy/(sintdt)+y/(sint)^2=0
z/(sint)^2*d^y/dt^2+y/(sint)^2=0，即d^2y/dt^2+y=0

Answer 2

dy/dt=-sintdy/dxd�0�5y/dt�0�5=d�0�5y/dx�0�5 *（dx/dt）�0�5+dy/dx*d�0�5x/dt�0�5=d�0�5y/dx�0�5 *sin�0�5t+（cost/sint*）*dy/dt把d�0�5y/dx�0�5 =cost/sin�0�5t*（-1/sint）dy/dt-y/sin�0�5t=-cost/sin�0�6t*dy/dt-y/sin�0�5t代入d�0�5y/dt�0�5+y=0