Question

Use for statements to find the values of x(t) = 3 cos (2?ft + 0.1) for t = 0,

01, 0.2, 0.3, 0.4 s when f =10, 15, and 20 Hz. Use one set ofstatements to compute the values for all three frequencies and store the results in a two-dimensional array. Use two nested for loops and double indexing.

Answer 1

Type the following code in MATLAB

     clc
    clear all
  
     t= 0:0.1:0.4;   
    f = 10:5:20;
   for f = 10:5:20
   for t= 0:0.1:0.4
      xt=3.*cos((2*pi.*f.*t)+0.1);

     xtt=[xt;f]           %making two d array of frequency and xt function output
end
end

REsult

xtt =

    2.9850                    %this is out put 
    10.0000                    %at 10hzfrequency    

xtt =

    2.9850
   10.0000

xtt =

    2.9850
   10.0000

xtt =

    2.9850
   10.0000

xtt =

    2.9850
   10.0000

xtt =

    2.9850
   15.0000

xtt =

   -2.9850
   15.0000

xtt =

    2.9850
   15.0000

xtt =

   -2.9850
   15.0000

xtt =

    2.9850
   15.0000

xtt =

    2.9850
   20.0000

xtt =

    2.9850
   20.0000

xtt =

    2.9850
   20.0000

xtt =

    2.9850
   20.0000

xtt =

    2.9850
   20.0000

Type the following code in MATLAB

%here we will also include time to see at what time at what frequency what is value ofx(t)

    clc
    clear all
  
     t= 0:0.1:0.4;
    f = 10:5:20;
   for f = 10:5:20
   for t= 0:0.1:0.4
      xt=3.*cos((2*pi.*f.*t)+0.1);

    xtt=[xt;f;t]                           %time parameter is included
end
end

Result

xtt =

    2.98501                    %output value of x(t)
   10.00000                     %at 10 hz frequency 
    0.00000                      %at time t=0 seconds

xtt =

    2.98501
   10.00000
    0.10000

xtt =

    2.98501
   10.00000
    0.20000

xtt =

    2.98501
   10.00000
    0.30000

xtt =

    2.98501
   10.00000
    0.40000

xtt =

    2.98501
   15.00000
    0.00000

xtt =

   -2.98501
   15.00000
    0.10000

xtt =

    2.98501
   15.00000
    0.20000

xtt =

   -2.98501
   15.00000
    0.30000

xtt =

    2.98501
   15.00000
    0.40000

xtt =

    2.98501
   20.00000
    0.00000

xtt =

    2.98501
   20.00000
    0.10000

xtt =

    2.98501
   20.00000
    0.20000

xtt =

    2.98501
   20.00000
    0.30000

xtt =

    2.98501
   20.00000
    0.40000