Example:
>> x=1:10
x =
1 2 3 4 5 6 7 8 9 10
>> y=rand(1,10)
y =
Columns 1 through 7
0.8147 0.9058 0.1270 0.9134 0.6324 0.0975 0.2785
Columns 8 through 10
0.5469 0.9575 0.9649
>> trapz(x(4:6),y(4:6))
ans =
1.1378
>>
