A problem in polar i want check my answer

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The discussion revolves around converting the complex number -3 - 5i into polar form. The initial calculation for the modulus (r) is correct at approximately 5.83, but there is confusion regarding the angle (Q). The angle was calculated incorrectly, as the tangent of Q should be based on the correct quadrant for the given coordinates. The need to use radians instead of degrees is emphasized due to the integer values involved. Clarification is sought on the proper calculation of the angle and the correct representation in polar form.
r-soy
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write in polar form ...elc
-3 - 5i

my answer :

x = -3 y = - 5

r = root (-3)^2 + (-5)^2
= 5.83

tan Q = 5/3 = -1.12
tan-1 -1.12 = -0.84
Q = -0.84
Q = -pi + -0.84 = -3.981

Polar form = 5.83e^(-3.981)i
 
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Ok first off:
I believe you've recorded your answer in exponential form.

Forms of Complex Numbers:

[PLAIN]https://dl.dropbox.com/u/4645835/MATH/ComplexForms.gif

Please correct me if I'm wrong.
 
Last edited by a moderator:
I think your angle may be wrong as well. This is what I did:

[PLAIN]https://dl.dropbox.com/u/4645835/MATH/Ex1.gif

I can explain why I added 180 degrees to the angle I calculated - if needed.
 
Last edited by a moderator:
Hi

but as I know in this question we change calculator to ( Rad ) nor (deg) because we have integer number -3 and - 5 not roots or ,

and please I want explaine more because I don't understand clearly
 
r-soy said:
write in polar form ...elc
-3 - 5i

my answer :

x = -3 y = - 5

r = root (-3)^2 + (-5)^2
= 5.83

tan Q = 5/3 = -1.12
tan Q = 5/3, but 5/3 is not equal to -1.12
r-soy said:
tan-1 -1.12 = -0.84
Q = -0.84
Q = -pi + -0.84 = -3.981

Polar form = 5.83e^(-3.981)i
 

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