Asked by christopher vinton
on 11 Sep 2019

Basically i want to normalize and display the maximum and minimum values between y and y2 for the following code so that they both display on the same plot

t=0:0.001:0.05;

y= 11.18*cos(60*pi*t+26.565);

y2= -60*pi*11.18*sin(60*pi*t+26.565);

title('Phasor Waveforms')

f1=max(y);

f2=max(y2);

hold on

plot(t,y)

plot(t,y2)

hold off

Answer by Star Strider
on 11 Sep 2019

Accepted Answer

Try this:

t=0:0.001:0.05;

y= 11.18*cos(60*pi*t+26.565);

y2= -60*pi*11.18*sin(60*pi*t+26.565);

title('Phasor Waveforms')

f1=max(y);

f2=max(y2);

figure

yyaxis left

plot(t,y)

yyaxis right

plot(t,y2)

christopher vinton
on 11 Sep 2019

this worked! thanks! but now i have a new error. trying to plot the max using this code:

idymax = find(y == max(y));

plot(t,y,'o',[idymax],'MarkerFaceColor','red','MarkerSize',15)

produced this error:

Error using plot

There is no o property on the Line class.

im using version 2019a, thank you so much for your time!

Star Strider
on 11 Sep 2019

As always, my pleasure!

I’m not sure what you want to do.

Try this:

t=0:0.001:0.05;

y= 11.18*cos(60*pi*t+26.565);

y2= -60*pi*11.18*sin(60*pi*t+26.565);

title('Phasor Waveforms')

f1=max(y);

f2=max(y2);

idymax = find(y == max(y));

figure

yyaxis left

plot(t,y)

hold on

plot(t(idymax),y(idymax),'o','MarkerFaceColor','red','MarkerSize',15)

hold off

yyaxis right

plot(t,y2)

If you want to plot a point or a series of values, the subscripts for those values need to be the same for all coordinates.

The find function will return the indices of all the values that are equal to ‘max(y)’ here. If there is only one ‘y’ maximum, an alternative could be:

[f1,idymax]=max(y);

since the max function will return the index to the first maximum it discovers.

Star Strider
on 11 Sep 2019

If you assign that logical operation to a variable it returns a logical vector of false (0) values, except for the maximum (true,1) to the variable:

q = y == max(y)

Otherwise, without the assignment, it does not appear to do the logical operation. (I did that experiment.)

Sign in to comment.

Answer by KSSV
on 11 Sep 2019

t=0:0.001:0.05;

y= 11.18*cos(60*pi*t+26.565);

y2= -60*pi*11.18*sin(60*pi*t+26.565);

title('Phasor Waveforms')

y=y/max(y) ;

y2=y2/max(y2) ;

[f1,idx1]=max(y);

[f2,idx2]=max(y2);

hold on

plot(t,y)

plot(t,y2)

plot(t(idx1),f1,'*r')

plot(t(idx2),f2,'*b')

hold off

Sign in to comment.

Opportunities for recent engineering grads.

Apply Today
## 0 Comments

Sign in to comment.