Hard complex no . q (1 Viewer)

[namburger]

http://i237.photobucket.com/albums/ff3/Namburger/Hardcomplexnoq.jpg

Can't get the last part

 

[sicmacao]

http://i237.photobucket.com/albums/ff3/Namburger/Hardcomplexnoq.jpg

Can't get the last part

(iii)
(a)
(u-w)/(u+w) = (u/w-1)/(u/w+1) (dividing the numerator and the denominator by w)
= (2i-1)/(2i+1)
=3/5+4/5i

(b) u+w = OV, u-w = UW by parallelogram law for vector addition and subtraction respectively.

So theta is equal to Arg[(u-w)/(u+w)]

cosx = 3/5, sinx = 4/5 => x is in 1st quadrant,
so tanx = sinx/cosx = 4/3

 

[namburger]

But all angles have a direction or -/+
Which one is it

Thanks anyway

 

[namburger]

actually dw. i reckon just the angle will give you the full marks. just curious.
http://en.wikipedia.org/wiki/Angle#Positive_and_negative_angles

 

[qqmore]

just curious, where did u get this qns from?

 

[namburger]

http://www.angelfire.com/ab7/fourunit/
http://au.geocities.com/ext2papers/
http://www.geocities.com/fourunitmaths/

1st paper of the 1st link