I want to plot this semi circle

Code:

%% Plotting The Semi Circle %%
%% Equation %%
%% After solving we came to know that r=wn %%
w_n=2.57;
r=w_n;
%% a is the angle which is 22 degrees %% 
a=22;
x=(r*cos(a));
y=(r*sin(a));
%% Final Plot %%
j=plot(x,y,'b')
%% Axis Limit Setting 
axis([-3 1 -3 3])
%% Setting Line width
set(j,'LineWidth',3)

Answer 1

[Voss]

I'm not sure where a equals 22 degrees comes from. That semicircle corresponds to an angle of 90 degrees to 270 degrees.

Setting a to a vector like 90:270 gives you a semicircle (and use cosd and sind since the angle is in degrees rather than radians).

%% Plotting The Semi Circle %%
%% Equation %%
%% After solving we came to know that r=wn %%
w_n=2.57;
r=w_n;

%% a is the angle which is 22 degrees %% 
% a=22;

a = 90:270;

% x=(r*cos(a));
% y=(r*sin(a));

x = r*cosd(a);
y = r*sind(a);

%% Final Plot %%
j=plot(x,y,'--g');          % '--g' to get a dashed green line

%% Axis Limit Setting 
% axis([-3 1 -3 3])
axis([-r-1 1 -r-1 r+1])     % "axes limits should be 1 unit greater than the r ..."

%% Setting Line width
set(j,'LineWidth',3)

[Waqas Shah]

Thank you very much

infact a comes from the sin inverse of damping factor for a specific Transfer function as "Theta" is eaual to sine inverse of that damping factor.

Anyways thanks agian ....

[Voss]

You're welcome!