作业帮菜鸟!急问!求助一个Mathematica做积分的问题!程序如下：In[1]:=6*1.1^3*NIntegrate[Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 + 0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,1000},{x,v,1000},{s,x,1000}] - 6*3*1.1^2*
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![菜鸟!急问!求助一个Mathematica做积分的问题!程序如下：In[1]:=6*1.1^3*NIntegrate[Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 + 0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,1000},{x,v,1000},{s,x,1000}] - 6*3*1.1^2*](/uploads/image/z/11424034-10-4.jpg?t=%E8%8F%9C%E9%B8%9F%21%E6%80%A5%E9%97%AE%21%E6%B1%82%E5%8A%A9%E4%B8%80%E4%B8%AAMathematica%E5%81%9A%E7%A7%AF%E5%88%86%E7%9A%84%E9%97%AE%E9%A2%98%21%E7%A8%8B%E5%BA%8F%E5%A6%82%E4%B8%8B%EF%BC%9AIn%5B1%5D%3A%3D6%2A1.1%5E3%2ANIntegrate%5BExp%5B-0.03%2A%28s+%2B+x+%2B+v%29+-+0.002%2A%28x%5E2+%2B+s%5E2+%2B+v%5E2%29%2F2+%2B+0.001%5E2%2F6%2A%28s%5E3+-+3%2As%2Ax%5E2+%2B+6%2Ax%5E3+-+12%2Ax%2Av%5E2+%2B+17%2Av%5E3%29%5D%2C%7Bv%2C0%2C1000%7D%2C%7Bx%2Cv%2C1000%7D%2C%7Bs%2Cx%2C1000%7D%5D+-+6%2A3%2A1.1%5E2%2A)
菜鸟!急问!求助一个Mathematica做积分的问题!程序如下：In[1]:=6*1.1^3*NIntegrate[Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 + 0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,1000},{x,v,1000},{s,x,1000}] - 6*3*1.1^2*
菜鸟!急问!求助一个Mathematica做积分的问题!
程序如下：
In[1]:=6*1.1^3*NIntegrate[
Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 +
0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,
1000},{x,v,1000},{s,x,1000}] -
6*3*1.1^2*
NIntegrate[
Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 +
0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,
1000},{x,v,1000},{s,x,1000}] +
2*3*1.1*NIntegrate[
Exp[-0.03*(s + 2*v) - 0.002*(s^2 + 2*v^2)/2 +
0.001^2/6*(17*s^3 + 12*v*s^2 + 4*v^3)],{v,0,1000},{s,0,
v}] + 2*3*1.1*
NIntegrate[
Exp[-0.03*(s + 2*v) - 0.002*(s^2 + 2*v^2)/2 +
0.001^2/6*(s^3 - 3*s*v^2 + 11*v^3)],{v,0,1000},{s,v,
1000}] +
6*3*1.1*NIntegrate[
Exp[-0.03*(s + u + v) - 0.002*(u^2 + s^2 + v^2)/2 +
0.001^2/6*(s^3 - 3*s*u^2 + 6*u^3 - 12*u*v^2 + 17*v^3)],{v,0,
1000},{u,v,1000},{s,u,1000}] - 6682.90
出来如下的结果：NIntegrate::slwcon:Numerical integration converging too slowly; suspect one of the following:singularity,value of the integration is 0,highly oscillatory integrand,or WorkingPrecision too small.>>
NIntegrate::slwcon:Numerical integration converging too slowly; suspect one of the following:singularity,value of the integration is 0,highly oscillatory integrand,or WorkingPrecision too small.>>
NIntegrate::slwcon:Numerical integration converging too slowly; suspect one of the following:singularity,value of the integration is 0,highly oscillatory integrand,or WorkingPrecision too small.>>
General::stop:Further output of NIntegrate::slwcon will be suppressed during this calculation.>>
Out[1]=2.704725569675203*10^1045
Ps.上面是积分限取1000的结果,积分限取800的时候等于1.321678837009696*10^357
可是积分的指数函数应该是收敛的.怎么会越来越大了呢?
菜鸟!急问!求助一个Mathematica做积分的问题!程序如下：In[1]:=6*1.1^3*NIntegrate[Exp[-0.03*(s + x + v) - 0.002*(x^2 + s^2 + v^2)/2 + 0.001^2/6*(s^3 - 3*s*x^2 + 6*x^3 - 12*x*v^2 + 17*v^3)],{v,0,1000},{x,v,1000},{s,x,1000}] - 6*3*1.1^2*
有奇点或者被积函数小于零,所以发散了哦.积分上限取800时出来的结果也是错的.你可以先把被积函数画出来,看是不是有奇点,然后可以分段积分,跳过奇点.