I need to add and multiply a vetor

Given a vector u = (u1 + u2 + ... + un) make a funcition which gives u1*u2+u2*u3+...+un-1*un. Apply it to the vector u = cos(0:pi/20:pi)

[Torsten]

And where is your code that doesn't work ?

Answer 1

[DGM]

You mean something like this?

u = cos(0:pi/20:pi);
v = sum(u(2:end) .* u(1:end-1))

v = 9.8769

[Luis]

Thank you very much

Answer 2

[Bora Eryilmaz]

This looks like the dot product of the subvectors u(1:n-1) and u(2:end):

u = cos(0:pi/20:pi); % Create the vector
p = u(1:end-1) * u(2:end)' % Use the dot product.

p = 9.8769

[Luis]

Thank you very much