1.

Let `z in C` be such that `|z| lt 1 `.If `omega =(5+3z)/(5(1-z)` thenA. `4 Im ( omega) gt 5`B. `5 Re (omega) gt 1`C. `5 Im(omega) lt 1 `D.

Answer» Correct Answer - B
Given complex number `omega=(5+3z)/(5(1-z))`
`rArr 5 omega -5 omega z=5+3z`
`rarr (3+5 omega)z=5 omega-5`
`rArr |3+5 omega||z|=|5 omega- 5|`
[applying modulus both sides and `|z_1z_2|=|z_2||z_2|]`
`therefore | z| lt 1 `
`therefore |3+5 omega| gt |5 omega - 5|" "["from Eq.(i)"]`
`rArr " "|omega+3/5| gt | omega-1|`
Let `omega` =x+iy, then `(x+3/5)^2+y^2 gt (x-1)^2+y^2`
`rArr x^2+9/25+6/5 x lt x^2 +1 -2x`
`rArr 16x/5 gt 16/25 rArr x gt 1/5 rArr lt 1`
`rArr 5 Re(omega ) gt 1`


Discussion

No Comment Found

Related InterviewSolutions