MATLAB: How to multiply 7 x 1 matrix with 400 x 1 matrix

matrix

How to multiply 7 x 1 matrix with 400 x 1 matrix?

It's matrix multiplication you can just transpose the matrix to match the rule of matrix multiplication:

a=rand(400,1); %example
b=rand(7,1);
ab=a*b.';      % -> b transposed here, now the size of b is 1 by 7
size(ab)     % which will be 400 by 7

See the following discussion:

You can plot it over a large range to see the trend

x = linspace(-1000, 1000);
y = @(x) 1./(1+10.^(x/400));
plot(x, y(x))

You can also put the value at infinity

>> y(inf)
ans =
     0
>> y(-inf)
ans =
     1

If you have symbolic toolbox

syms x
y = 1/(1+10^(x/400));
fplot(y, [-1000 1000])

And find the limits

>> limit(y, x, inf)
ans =
0
>> limit(y, x, -inf)
ans =
1