Dimensional error while running the code from matlab documentation

fs = 1e3;
t = 0:1/fs:1;
x = [2 1 2]*sin(2*pi*[50 150 250]'.*t) + randn(size(t))/10;

in this code the dimension of the t mismatches with [50 150 200]'. how could i possibly get the output without dimesnsional error?

Answer 1

[Tommy]

This code should run without error in R2016b and later due to implicit expansion, as t is a row vector and [50 150 200]' is a column vector. This is similar to

>> [1;2].*[1:10]
ans =
     1     2     3     4     5     6     7     8     9    10
     2     4     6     8    10    12    14    16    18    20

which might also be expected to result in an error.

See https://blogs.mathworks.com/loren/2016/10/24/matlab-arithmetic-expands-in-r2016b/ and https://stackoverflow.com/questions/47298743/element-wise-mutiplication-of-vectors-gives-matrix-in-matlab for detailed explanations.

[Vijayavelu SS]

Thank you