Pls share ur ideas i wish to knw were i have gone wrong or is the text answr is wrong pls help(Headbang)(Headbang)(Headbang)

Printable View

- July 9th 2013, 06:49 AMspacemenoncomplex number in polar form argument and modulus doubt
Pls share ur ideas i wish to knw were i have gone wrong or is the text answr is wrong pls help(Headbang)(Headbang)(Headbang)

- July 9th 2013, 06:53 AMProve ItRe: complex number in polar form argument and modulus doubt
It helps if ALL of your PDF can be read. Is your original complex number ?

- July 9th 2013, 07:13 AMspacemenonRe: complex number in polar form argument and modulus doubt
yes yes

- July 9th 2013, 08:05 AMProve ItRe: complex number in polar form argument and modulus doubt
I agree with your evaluation of . As for you will need to consider nine separate cases...

Case 1: is in the first quadrant, so and . The first is true for all except the integer multiples of , and the second is true in the region and the addition of all integer multiples of for this region. Therefore, is in the first quadrant when or any integer multiple of being added to this region.

When we have a in this domain, then

Case 2: is in the second quadrant, so and . The first of these is never true, so your complex number can never be in the second quadrant.

Case 3: is in the third quadrant, so and . The first of these is never true, so your complex number can never be in the third quadrant.

Case 4: is in the fourth quadrant, so and . The first of these is true for all except the integer multiples of , and the second is true when or the addition of any multiples of to this region. So when satisfies this case, then

The other cases are when your complex number lies on the positive real axis, the negative real axis, the positive imaginary axis, the negative imaginary axis, and the origin. See how you go with the rest of them :) - July 9th 2013, 05:49 PMspacemenonRe: complex number in polar form argument and modulus doubt
Thank u,but wen z=x+iy ,arg z = tan inverse(y/x),then arg of 1-z= -sin2(theta)/1-cos2(theta) bt u did the prb other way round am i mistaken

- July 9th 2013, 05:55 PMspacemenonRe: complex number in polar form argument and modulus doubt
my main question is even by thinking ur way arg (1-z)=pi/2 +theta ,since case1 is 0<theta<pi ,it wont lie in secnd quadrant so has to lie in first quadrant,but answer in text says arg(1-z)=theta- pi/2

- July 9th 2013, 06:30 PMPlatoRe: complex number in polar form argument and modulus doubt
- July 9th 2013, 07:17 PMProve ItRe: complex number in polar form argument and modulus doubt
- July 9th 2013, 07:21 PMspacemenonRe: complex number in polar form argument and modulus doubt
i am sorry bt u didnt answer this part of the question, u wrote

arg 1-z = arctan(1-cos2theta/sin2theta) instead of arg 1-z= arctan(-sin2(theta)/1-cos2(theta) ) why? - July 9th 2013, 07:23 PMspacemenonRe: complex number in polar form argument and modulus doubt
sry u already answered that i didnt see the post

- July 9th 2013, 07:36 PMspacemenonRe: complex number in polar form argument and modulus doubt
so arg(1-z) =pi/2 +theta and mod(1-z)= 2sin (theta)

so according to ur theory y coordinatte is -sin2(theta) and x co0rdinate is 1-cos (2theta)

so case 1: 0<theta< pi

the complex no shld lie in 2nd quadrant as first quadrant -sin2theta is nt positive so only possibilty is second quadrant ,therfore we conclude x<0 and y >0 so arg(1-z) = pi/2+theta -pi =-pi/2+theta