Complex Numbers And Quadratic Equations question 366

Question: If $ {\log_{\sqrt{3}}}( \frac{|z{{|}^{2}}-|z|+1}{2+|z|} ) $ $ <2 $ , then the locus of $ z $ is

Options:

A) $ |z|=5 $

B) $ |z|<5 $

C) $ |z|>5 $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

We have $ {\log_{\sqrt{3}}}( \frac{|z{{|}^{2}}-|z|+1}{2+|z|} )<2 $
Þ $ \frac{|z{{|}^{2}}-|z|+1}{2+|z|}<{{(\sqrt{3})}^{2}} $
Þ $ |z{{|}^{2}}-4|z|-5<0 $
Þ $ -1<|z|<5 $
Þ $ |z|<5 $ as $ |z|>0 $ \ Locus of $ z $ is |z|<5