Complex number...

Q.1
If |z|=1
then prove that complex number denoted by √(1+z)/(1-z) always lie in either of the two fixed perpendicular lines..

Q.2
If z1+z2+z3=0. then prove that the angle between any two pair of complex number is greater than equal to 2Ï€/3

8 Answers

62
Lokesh Verma ·

Q 1 was solved sometime back on the forum.. I think it was given by eureka.. i will have to check..

33
Abhishek Priyam ·

ok.. khoj lete hain..

62
Lokesh Verma ·

http://targetiit.com/iit_jee_forum/posts/complex_geometry_295.html

341
Hari Shankar ·

Q 1.

z lies on a circle for which the line joining (1,0) and (-1,0) are the ends of a diameter.

That means arg(1+z/1-z) = ±π/2.

Hence the argument of the square root of the number is ± π/4. Thus, the numbers lie on one of two perpendicular lines.

Q 2. Needs to be rephrased I guess. It should be: there exists a pair such that the angle between them is greater than or equal to 2Ï€/3.

Please check

62
Lokesh Verma ·

this proof for the first part is awesome :)

I wonder how much I have to learn to equal prophet :)

62
Lokesh Verma ·

but then this was doable ;)

1
mkagenius ·

BHAIYA HOW TO APPROACH GRAPHICALLY....

62
Lokesh Verma ·

Rotation as done by Prophet is a graphical method if u understand it well enuf :)

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