3 questions from complex numbers

Q1 If a≠b,then equation zz+az+bz+c=0 represents ?

Q2 If a=b,c εR and lbl2>c ,then equation zz+az+bz+c=0 represents ?

Q3 If a=b,c εR and lbl2<c ,then equation zz+az+bz+c=0 represents ?

3 Answers

106
Asish Mahapatra ·

Q2. zz + az + bz +c =0

x2+y2 + (c+id)(x+iy) + (c-id)(x-iy) +k =0
=> x2+y2 + cx - dy + cx + dy + k =0
=> x2+y2 + 2cx + k =0

this represents a circle with centre (-c,0) and radius √c2-k (this may represent a circle or may not)

Q3. the exp is same but as given c2+d2 < k
So the radius turns out to be imaginary,, So this represents nothing i guess.

24
eureka123 ·

ur answers are right..but i expected some unconventional solution...

btw a doubt..what is the use of a=b and other cond of these kind?

1
Grandmaster ·

i cannot understand how relation betw a and b would affect the question

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