Syntax to calculate sum with maxima or wxmaxima using different variables So I'm not sure if I'm right here but I can try:
So we are having a statistics class at uni. The question is:
$x_{1}= 5$, $x_{2}= 3$, $x_{3}= 7$ 
$y_{1}= 6$, $y_{2}= 4$, $y_{3}= 12$
Calculate following: 
$\sum_{i=2}^{3}(x_{i}+y_{i}) =$
I know it's actually quit trivial to calculate this by hand but I would really like to know how I can calculate such stuff using wxmaxima.
Can anybody help me?

(Give a man a fish)
x:[5,3,7]; 
y:[6,4,12]; 
sum(x[i]+y[i], i, 2, 3); 

(Teach a man to fish ;) 
At the wxmaxima command line, type describe(sum) or example(sum)
(The parenthetical remarks refer to an old saying, my favorite version of which is, "Build a man a fire and he'll be warm for a night.  Set a man on fire and he'll be warm for the rest of his life.")
