how can i use sigma (summation ) in loop

how can i use sigma i.e summation in a loop

Answer 1

[Chunru]

% The input data
mc = 10;
a = randi(mc, 1);       % alpha
l = randi(mc, 1);       % l

b = sum((pi-a).*l)/(4*pi)

b = -0.4099

[NAGA LAKSHMI KALYANI MOVVA]

Thankyou..