(3+i)/(9-i)3+i9−i Z=a+ib Z=a+ib. Modulus: |Z|=sqrt (a^2+b^2)|Z|=√a2+b2;
Argument: theta=tan^-1(b/a)θ=tan−1(ba) Trigonometrical form :
Z =|Z|(costheta+isintheta);Z_1= 3+ i Z=|Z|(cosθ+isinθ);Z1=3+i.
Modulus:|Z_1|=sqrt(3^2+1^2)~~ 3.16 |Z1|=√32+12≈3.16
Argument: tan alpha= (|1|)/(|3|):. alpha = tan^-1(1/3)~~0.32
Z_1 lies on first quadrant, so theta =alpha ~~ 0.32
:. Z_1=3.16(cos 0.32+isin 0.32)
Z_2= 9 - i . Modulus:|Z_2|=sqrt(9^2+1^2)
=sqrt 82~~ 9.06 Argument: tan alpha= (|-1|)/(|9|)
=1/9 :.alpha =tan^-1 (1/9) = 0.11 ; Z_2 lies on fourth
quadrant.:. theta=2pi-alpha ~~6.17
:. Z_2=9.06(cos 6.17+isin 6.17) :. (3+i)/(9-i) =
Z= (3.16(cos0.32+isin 0.32))/(9.06(cos 6.17+isin6.17)
Z=0.35(cos(0.32-6.17)+isin (0.32-6.17)) or
Z=0.35(cos 5.85 +i sin 5.85) =13/41+6/41 i
In trigonometric form; 0.35(cos 5.85 +i sin 5.85)