- Exam
- JEE Main
- Year
- 2021
- Date
- 16 March
- Shift
- Evening Shift
- Subject
- Mathematics
- Chapter
- Complex Number
JEE Main 2021 · 16 March · Evening Shift · Mathematics · Complex Number
The least value of |z| where z is complex number which satisfies...
The least value of where is complex number which satisfies the inequality , is equal to :
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
{e}^{\left(\dfrac{\left(\left|z\right| + 3\right)\left(\left|z\right| - 1\right)}{\left|\left|z\right| + 1\right|}\log_{e}2\right)} \ge \log_{\sqrt{2}}\left|5\sqrt{7} + 9i\right|⇒ 2\dfrac{\left(\left|z\right| + 3\right)\left(\left|z\right| - 1\right)}{\left(\left|z\right| + 1\right)} \ge lo{g}_{\sqrt{2}}\left(16\right)⇒ 2\dfrac{\left(\left|z\right| + 3\right)\left(\left|z\right| - 1\right)}{\left(\left|z\right| + 1\right)} \ge {2}^{3}\dfrac{\left(\left|z\right| + 3\right)\left(\left|z\right| - 1\right)}{\left(\left|z\right| + 1\right)} \ge 3
⇒ \left|z\right| \ge 3 ⇒ {\left|z\right|}_\min = 3