Introduction to Numerical Sums, Products, and Integrals

NSum[f,{i,imin,Infinity}]numerical approximation to
NProduct[f,{i,imin,Infinity}]numerical approximation to
NIntegrate[f,{x,xmin,xmax}]numerical approximation to
NIntegrate[f,{x,xmin,xmax},{y,ymin,ymax}]
the multiple integral

Numerical sums, products, and integrals.

Here is a numerical approximation to .
In[1]:=
Click for copyable input
Out[1]=
NIntegrate can handle singularities in the integration region.
In[2]:=
Click for copyable input
Out[2]=
You can do numerical integrals over infinite regions.
In[3]:=
Click for copyable input
Out[3]=
Here is a double integral over a triangular domain. Note the order in which the variables are given.
In[4]:=
Click for copyable input
Out[4]=
Here is a double integral over a more complicated domain.
In[5]:=
Click for copyable input
Out[5]=