Question

Question 10 If z1= 2-i, z2 = 1+i, find | (z1+z2+1) / (z1-z2+1) |.

Class X1 - Maths -Complex Numbers and Quadratic Equations Page 113

Answer 1

z1 = 2 - i
z2 = 1 + i ,

|z1 + z2 + 1| /|z1 - z2 + 1|
= | (2 - i) + (1 + i) +1|/|(2 - i) -(1+ i) + 1 |
= | 4|/| 2 - 2i|
= 2/| 1 - i|
= 2/√{1²+ (-1)²} [ we know, z = ±a ± ib , |z| = √(a²+ b²) ]
= 2/√2
= √2

Answer 2

It is wrong answer ok correct it