Question
Question: If log<sub>1/2</sub>\(\frac{|z|^{2} + 2|z| + 4}{2|z|^{2} + 1}\)\< 0 then the region...
If log1/22∣z∣2+1∣z∣2+2∣z∣+4< 0 then the region
A
1 < | z | < 3
B
| z | < 2
C
| z | < 3
D
| z | > 1
Answer
| z | < 3
Explanation
Solution
Sol. log1/22∣z∣2+1∣z∣2+2∣z∣+4<0
2∣z∣2+1∣z∣2+2∣z∣+4>(21)0
∣z∣2−2∣z∣−3 < 0
(| z | – 3) (| z | + 1) < 0
| z | < 3