ep2_p3.m

此代码展示了Euler计算方法与差分方法

%  Ep2_p3: << 实验二 >>  摄动方法   算式（2.18） --- 符号运算 
%  Designed by FGH

%   求解析解

syms r e a b A B
 
 y1= int(r/sqrt(1-r^2),0,1)
 g1= a*b*int(y1,e,0,2*pi)
 
  y2= int( (A*cos(e)^2+B*sin(e)^2)*r^3/(2*sqrt(1-r^2)),r,0,1)
 g2= a*b*int(y2,e,0,2*pi)
 
 y3= int( (A*cos(e)^2+B*sin(e)^2)^2*r^5/(8*sqrt(1-r^2)),r,0,1)
 g3= a*b*int(y3,e,0,2*pi)

 s= g1+g2-g3
 
 pause
 
 %   求数值解
 
clear 
a= 30.6;
b= 29.6;
A= -0.03883;
B= 0.02721;
syms r e 
 
 y1= int(r/sqrt(1-r^2),0,1)
 g1= a*b*int(y1,e,0,2*pi)
 
  y2= int( (A*cos(e)^2+B*sin(e)^2)*r^3/(2*sqrt(1-r^2)),r,0,1)
 g2= a*b*int(y2,e,0,2*pi)
 
 y3= int( (A*cos(e)^2+B*sin(e)^2)^2*r^5/(8*sqrt(1-r^2)),r,0,1)
 g3= a*b*int(y3,e,0,2*pi)

 S= double(g1+g2-g3);
 sprintf('       S = %7.2f\n',S)