Manipal MET2020MathematicsComplex Number
If Z₁=1+i, Z₂=-2+3 i and Z₃= a l 3 are collinear, where i^2=-1 , then the value of a will be
Options
- A-1
- B3
- C4
- D5
Correct answer
D. 5
Step-by-step solution
Given complex númbers are Z₁=(1+i) (1,1)= (a₁, b₁ )Z₂=(-2+3 i) (-2,3) (a₂, b₂ ) and Z₃= a i 3 = (0, a 3 ) (a₃, b₃ ) These three points will be collinear, if 1 2 [a₁ (b₂-b₃ )+a₂ (b₃-b₁ )+a₃ (b₁-b₂ ) ]=0 array cc & 1 (3- a 3 )-2 ( a 3 -1 )+ (1-3)=0 & 9-a 3 -2 ( a-3 3 )+0=0 & 9-a-2 a+6=0 & 3 a=15 & a=5 array