Small Help in MatLap ( square matrix ? )

[ahmedking]

Small Help in MatLap ( square matrix ?!? )

>> n=-5:0.01:17;
>> u=1;
>> x=0.7^n*u(n);
? Error using ==> mpower
Matrix must be square.

how can i solve this problem

as iam a beginner in the matlap :)the main question is

plot the following discrete functions

1- x[n]=0.7^n*u[n] -5<n<17

please help me thanks in advance

 

[ahmedking]

please help i need it urgently :)

 

[Mark44]

how can i solve this problem

as iam a beginner in the matlap :)

I'm pretty sure you mean matlab.

>> n=-5:0.01:17;
>> u=1;
>> x=0.7^n*u(n);
? Error using ==> mpower
Matrix must be square.

Your variable n is an array, so you need to use the element-by-element power operator, which is .^

Also, you are setting u to 1 in the second line, above, but u appears to be an array in the third line. You're going to run into another problem with u(n), since the index of an array has to be an integer >= 1. IOW, the value of n must be an integer >= 1 in an expression u(n).

Here's a link to some documentation on MATLAB. I have found it to be pretty helpful.
http://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/getstart.pdf

the main question is

plot the following discrete functions

1- x[n]=0.7^n*u[n] -5<n<17

please help me thanks in advance