what does this u[1] represents in the following equation??

*cos(u[1]*2pi*f1)*in this u[1] means what???

similarly in this equation:[refer the below image]

(2/3)(u[1]+u[2]*cos(2*pi/3)+u[3]*cos(4*pi/3))*

u[2],u[3] means what?

please explain me.check the image for the equations.

Answer 1

[John D'Errico]

u[1] represents a syntax error in matlab.

Or, rather, I should say that it IS a syntax error. If you wish to index a variable, as u(1) would do, you use parens, not square brackets.

[balaji`]

dude its clearly given as [] and not() please someone explain it.

Answer 2

[Walter Roberson]

You are reading code written in some other computer language. Depending in the computer language, u[T] might be the same as Matlab's u(T), or it might be the same as Matlab's u(T+1). As there is no u[0] referenced, it is most likely that u[1] is Matlab's u(1)

Matlab's symbolic toolbox uses the [] notation for subscripting.

Note by the way that 2pi is not valid Matlab syntax: you would need 2*pi in Matlab.

[Walter Roberson]

I checked the diagram; the [] very likely represent subscripting and should be changed to () for use in Matlab.

[balaji`]

that's ok.what does it mean there??

the term is cos(2*pi*f*t) that is given as cos(2*pi*f*u[1]) how is this both related??

[Walter Roberson]

I do not see cos(2*pi*f*t) in the diagram?

If you are looking at some reference material for State Vector PVM then it would help to post a URL for it, so that we could read the equations in context.

Answer 3

[Paulo Silva]

u[1] means first value of the input vector u

I think simulink changed the way it represents u[1], open a Fcn block and see if it's u(1) or u[1], it's the same thing, new versions got u(1).

It means that u is a bunch of values, something similar to this 3 6 5 4 6 5 6... in this simple case u[1] is equal to 3 because 3 is the value of the first element of the vector.