Complex things

find the reflection of the complex no. 2-i in the straight line

z = iz

14 Answers

11
SANDIPAN CHAKRABORTY ·

is the answer 1-2i ??????

11
SANDIPAN CHAKRABORTY ·

this is the way i did it......

I ve taken z = iz as the line x+y=0 ths part i'm not sure whether i am right...

so the reflection of 2-i i.e (2,-1) in the line x+y=0 is coming out to be (1,-2) i.e 1-2i

please point out my mistake if am wrong somewhere...

1
Manmay kumar Mohanty ·

now given equation of straight line is y = -x
hence reflection of 2,-1 abt y= - x is 1 , -2
hence required complex no. is 1 - 2i

hence required answer [1]

1
student ·

z(bar)=iz
is
y=x

reason

take
z = a+ia
z(bar)=a-ia
z=iz(bar) rotation by 90 degree

so it shud be

y=x

let reflection be

x,y

now we have

2+x=y-1
y=x+3

also we have

1+y=2-x

y=1-x

solve both

we get
x=-1 .y=2

so answer is

(-1,2i )

11
SANDIPAN CHAKRABORTY ·

but where am i wrong...plz see the graph that i used....whhy is it not y=-x....

plz tell me where i am going wrong.... [2]

1
student ·

nope i was wrong
i took direction of rotation wrong

1
student ·

proof by graph

take

z=x-ix

now rotate it by 90 in anticlockwise direction

hence

iz= =z(bar)

11
SANDIPAN CHAKRABORTY ·

but RSP bhaiya is it necessary to take z=x-ix...why cant we take z=x+ix....
[12]

1
SURYA RAMKUMAR ·

i suppose it is done oral[3][3]........n answer i suppose shud come[1-2i]

1
SURYA RAMKUMAR ·

are u sure rpf.... wat u wanted to prove???[3][3].......LOL!!!!!

1
student ·

i proved that y=-x is the locus !

1
student ·

if u didnt understand plese see coni's theorem [1]

11
SANDIPAN CHAKRABORTY ·

so am i rite ??.....(#2,#3,#6)................[12]

1
SURYA RAMKUMAR ·

@sandipan...........no doubt...u r a genius man[1]
@rpf........i knew it man....just saying was it really needed???[1]

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