Question

Find this difficult o.O please help :0

Answer 1

http://screencast.com/t/vfKNEvvdk

Answer 2

@ganeshie8

Answer 3

@Vincent-Lyon.Fr @ParthKohli

Answer 4

@kc_kennylau

Answer 5

Which part?

Answer 6

ii)

Answer 7

Okay, follow the instruction and square both sides first?

Answer 8

can u show da wrking

Answer 9

\[\Large\begin{array}{rcl}
|z-10i|&=&2|z-4i|\\
|(a+bi)-10i|&=&2|(a+bi)-4i|\\
|a+(b-10)i|&=&2|a+(b-4)i|\\
a^2+(b-10)^2&=&4a^2+4(b-4)^2\\
a^2+b^2-20b+100&=&4a^2+4b^2-32b+64\\
-3(a^2+b^2)+12b+36&=&0\\
-3(|z|^2)+12(\tfrac{iz^*-iz}2)+36&=&0\\
|z|^2-2(iz^*-iz)-12&=&0\\
zz^*-2iz^*+2iz-12&=&0
\end{array}\]

Answer 10

Appendix: iz*-iz = i(a-bi) - i(a+bi) = ai - bi^2 -ai - bi^2 = 2b

Answer 11

Any step you don't understand?

Answer 12

Key ideas: \(|a+bi|=\sqrt{a^2+b^2}\), \(zz^*=|z|^2\)

Answer 13

\[a=\frac{z+z^*}2\]\[b=\frac{iz^*-iz}2\]