Why is does the y axis of the graph have the same value all the way down?

Hello, I am very new to Matlab and I have just started learning to produce graphs. I tried to run the code:

y =@(t) 1.11*cos(2*pi*100000*t) + 0.5*cos(2*pi*98000*t) + 0.5*cos(2*pi*102000*t); x = -1*pi:0.1:pi; plot(x,y(x));

The graph produced is:

As you can see, it has -0.145 all the way down the y axis and I have no idea why. Is this a problem with the code? Thank you very much in advance!

Answer 1

[Konstantinos Sofos]

Are you sure that your formula is correct? You pass into cosine function not pi but pi^2 when you plot. You pass into variable t the vector x when you plot and this vector x is already the range of pi.

if you use instead

 y =@(t) 1.11*cos(100000*t) + 0.5*cos(98000*t) + 0.5*cos(102000*t); x = -2*pi:0.1:2*pi;
  plot(x,y(x))

you take

if the function is correct you have to take another interval

x = -pi:pi/180:pi

Regards

[pp6g]

Thanks for the help!!!

Answer 2

[Giorgos Papakonstantinou]

Because y(x) barely changes in the interval 1*pi:0.1:pi.

Try a more densely spaced vector: i.e.

x = -1*pi:pi/180:pi;

[pp6g]

Thanks for the help!!!