Thomas O'Sullivan's Mathematics & Physics Pages
The Sigma notation for summation of series.
The sum of a sequence can be written as: 
Note: 

The following formulae should be learned : Note: When using these formulae the upper and lower limits are often left out. 
etc. 

Sigma and Geometric Progressions etc. 
Sigma and Surds Note in this example and the next one, u_{n} may have to be manipulated (L.C. Paper 1 1995 q. 4(b)) to give the forms shown, This is a telescoping series. 
Sigma and Partial Fractions 
© Thomas G. O'Sullivan 1999