plotting lines

i have a simple ques that if i have z-plane having x and y axes,and i express z=x+i*y,and x if fixed let say 5 any y=0:10 then how can i plot this thing,please guide me,i m waiting for reply

[Muhammad Usman]

yes i is imaginaryunit

Answer 1

[bym]

y = 1:10;
x=5*ones(size(y));
z=x+i*y;
plot(real(z),imag(z))

[Walter Roberson]

That will not be able to show the values of x and y on the axes.

Answer 2

[Mohsen Davarynejad]

y = [0:.1:10]
plot(5,y)
xlabel('Re')
ylabel('Im')

http://en.wikipedia.org/wiki/Imaginary_number

[Walter Roberson]

What about z? y is not the imaginary quantity.

My recollection is that if you plot a scalar x against a row vector y, that you end up with a single (probably invisible) point, but that if you plot a scalar x against a column vector y, you will get a line. It is, my memory says, an exception to the "row vector is automatically converted to column vector" rule, and happens because the size of x (i.e., one) happens to match the first dimension of y (i.e., one for a row vector)

[Mohsen Davarynejad]

If z = x + yi, then x is the "real part" and y is the "imaginary part". When x is a constant and y is vector, then you will have line in the complex plane. No?

http://en.wikipedia.org/wiki/Imaginary_number

[Walter Roberson]

z might be a line in the complex plane, but plot(5,y) does not involve z at all, and plot(5,z) would be refused because it is not allowed to plot complex data except through plot(z) which in turn is the same as plot(real(z),imag(z)) -- real vs imaginary.

Answer 3

[Walter Roberson]

y = 0:10;
x = 5 * ones(size(y));
z = x + i * y;

Now, if "i" were a real-valued constant, you would then use

plot3(x, y, z)

However, "i" is the complex constant, so you have a line in complex space, and there is no way to draw that in one step. Instead you would need to use something like,

plot3(x, y, real(z), 'r', x, y, imag(z), 'g', x, y, abs(z), 'b')

or perhaps plot 3 separate images using subplot()

[Muhammad Usman]

i just tried your code where "i" is complex constant...now i want to ask that how can a draw a rectangle shape and color it on the axes,i.e.let x=0:5 and y=0:7 and these lines meet at(5,7),so guide me.