二重积分求值

uaidenp

计算二重积分的时候，结果就是一个式子，不是积分值，这是为什么呢？求教

1 W) D' ]( g7 k" `6 U代码如下：

clear all
& q) \. Y+ b- s) u7 ~( \2 \3 Aclose all
clc
5 |! T7 a, e! k8 R4 wsyms x y
" ^; G3 n3 r" `; A" [  e0 ]1 Womega=1;
2 Y" [' h! ?3 ?0 P) c$ ~- Emu=0.001;
: I" J  |$ B; {) _0 q# K6 h( Walpha=0.13;
- B6 D; Y1 V$ j5 [  ~: N8 Abeta=0.0031;
u=0.001;v=-0.02;
2 q9 G1 u2 c; L4 D9 P* P- b+ T, \tau=2.2;tau1=1.5;D=0.11;
tau01=1.42;tau02=1.5;tau03=1.56;tau04=1.9;
$ e- J# n- i! g) d6 o- e' L' Uomega2=1-u*cos(omega*tau)-v*omega*sin(omega*tau01);
eta=1+(1/mu)*(-(u/omega)*sin(omega*tau)+v*cos(omega*tau01));
8 S* G; n) m; i* PK=D/(omega2.*(1+omega2.*(tau1.^2)));
f1=(1./(omega2.*K)).*exp(-(mu./(1536.*K)).*(15.*beta.*(x.^2+y.^2./omega2).^4-32.*alpha.*(x.^2+y.^2./omega2).^3+96.*(x.^2+y.^2./omega2).^2-768.*eta.*(x.^2+y.^2./omega2)));
F1=int(int(f1,x,0,10),y,-10,10)


! F6 \0 A/ Z/ ?* U$ m
  K1 O- d$ {$ n$ U2 M/ L结果：
+ `$ b* E* s- ]; p, w% l7 CF1=
int(int((1029484437153*exp((76368780973521777*(x^2 + (2251799813685248*y^2)/2297649917499219)^3)/922337203685477580800 - (17623564840043487*(x^2 + (2251799813685248*y^2)/2297649917499219)^2)/9223372036854775808 - (546330510041348097*(x^2 + (2251799813685248*y^2)/2297649917499219)^4)/590295810358705651712000 - (3488543873076974433998624506509*x^2)/81129638414606681695789005144064 - (1162847957692324811332874835503*y^2)/27593854166072889506733609713664))/34359738368, x, 0, 10), y, -10, 10)

7 m8 C" }, T. N; W( b6 F
  s8 N8 o/ G* w% _2 F! H: [* L

llbnmo

积分结果是个关于y的函数，如何转化成具体数值呢

lupkpu9

double(F1)
  h" N* k5 W3 A  \* @- S( R第一句加上这个

uaidenp

lupkpu9 发表于 2020-7-2 10:16
; {5 l# u) x  P% }7 fdouble(F1)
第一句加上这个

0 I' ~) ]1 q5 e2 G& r可以了，谢谢哦
9 ?8 y2 b9 g0 Z) Y+ l( o+ P( T+ ^) c* e

勇往直前11

来学习一下