If z is a vector , what is the difference between angle(z) and atan2(z)

If z is a vector z=x+j*y, what is the difference between angle(z) and atan2(z)

becuae when I used angle(x+i*.y) gives a differen results

this is the matlab code

clc

clear

close all

f=50;w=2*pi*f;Tperiod=1/f;Tmax=4*Tperiod;Dt=Tperiod/(6*f);N=(Tmax/Dt)+1;

t0=0.00001;

t=zeros(N,1); Bmx=zeros(N,1); Bmy=zeros(N,1);

thetaB=90;Bmax=1.6;

for k=1:N+1

t(k)=t0+Dt*(k-1);

Bmx(k)=Bmax*sin(w*t(k));

Bmy(k)=Bmax*sin(w*t(k)-(thetaB)*pi/180);

end

z=Bmx+i*Bmy;

figure(1);

plot(z,'k*')

hold on

plot(Bmx,Bmy,'r','LineWidth',2)

figure(2)

P1 = atan2(Bmy,Bmx);

P2=1.6.*(180/pi).*angle(Bmx+i.*Bmy);

P3=1.6.*(180/pi).*angle(z);

hold on

plot(P1,'k*')

plot(P2,'r','LineWidth',2)

plot(P3,'b','LineWidth',2)

[John D'Errico]

You could not possibly have used atan2, becuase atan2 does not work with only one argument.

Answer 1

[John D'Errico]

Perhaps you did not use atan2 properly. Consider this example:

z = [1+i,1-i,-1+i,-1-i];
angle(z)

ans = 1×4

0.7854 -0.7854 2.3562 -2.3562

atan2(imag(z),real(z))

ans = 1×4

0.7854 -0.7854 2.3562 -2.3562

If you want the result in degrees, this is not difficult. In fact, with atan2d, it already does the conversion for you to degrees.

angle(z)*180/pi

ans = 1×4

45 -45 135 -135

atan2d(imag(z),real(z))

ans = 1×4

45 -45 135 -135

The two functions will be compatible, as long as you use them properly. remember that atan2 is a TWO argument utility. You need to separate out the real and imaginary parts to use atan2 or atan2d.

[Hassan Abdelazeem]

Thnak you indeed for your answer

Answer 2

[Paul]

atan2() returns the answer in radians. So multiply it by 180/pi as for P2 and P3 (or use atan2d(), though atan2d() might result in small numerical differences). And P1 will also need to be multiplied by 1.6 to match P2 and P3.

[John D'Errico]

angle also returns a result in radians.

angle(1+i)

ans = 0.7854

That is radians, NOT degrees.

[Paul]

Absolutely. Which is why, P1 needs to be include the 1.6*(*180/pi) factor as applied to P2 and P3.

[Hassan Abdelazeem]

thank you for your answer

So, I can use these functions to determine the lag angle between the real and the imaginary part?