Sum of specific elements in a column matrix

Say I have a column matrix [1;2;3;4;5;6;7;8;9]. I want to add the elements from row 3 to row 9.

So the result will come as 42

Answer 1

[madhan ravi]

a=[1;2;3;4;5;6;7;8;9];
sum(a(3:size(a,1)))     % size(a,1) can be whichever element you wish

command window:

ans =

    42