How can I plot a horizontal line for a polar plot?

I have a polar plot of two lines with an equation to get the percent error between them. How do I plot a horzontal line where the percent error is at 5%?

Code is below.

Thanks in advance.

alpha = 0:0.01:(1/2) * pi;
y = sin(alpha);

polarplot(alpha,y)                         %first plot
pause(1)
hold on

polarplot(y.*(alpha)==alpha)               %second plot

pError = 100*(alpha-sin(alpha))./sin(alpha); %percent difference
disp(pError);
pause(1)

polarplot(pError .* .05)  %horizontal line at 5% error

hold off 

[Star Strider]

It looks as though you already did that:

polarplot(pError .* .05)  %horizontal line at 5% error

What do you want it to be?

[Christian Bellew]

Yes, but it plots a curved line instead of a horizontal one. I would like the horizontal line to be where the error reaches 5%.

Answer 1

[Star Strider]

This plots the horizontal line:

polarplot(acos(pError)./asin(pError) * 0.05/max(pError), 'LineWidth',1)  %horizontal line at 5% error

I am not sure how to scale it to be certain it meets the 5% criterion, since I am not certain what you are doing.

Another option:

polarplot(acos(pError-2*pi)./asin(pError-2*pi) * 0.05/max(pError), 'LineWidth',2)  %horizontal line at 5% error

I defer to you for the proper scaling.

.

[Christian Bellew]

Thank you!

[Star Strider]

As always, my pleasure!