Q62.Let z ≠−i be any complex number such that z+iz−i is a purely imaginary number. Then z + 1z is: (1) 0 (2) any non-zero real number other than 1 . (3) any non-zero real number. (4) a purely imaginary number. Q63.8-digit numbers are formed using the digits 1, 1, 2, 2, 2, 3, 4, 4. The number of such numbers in which the odd digits do no occupy odd places, is: (1) 160 (2) 120 (3) 60 (4) 48
What This Question Tests
The problem requires using the definition of a purely imaginary number and complex conjugates to determine the modulus of z, and then simplifying the expression z + 1/z based on this property.
Concepts Tested
Formulas Used
If w is purely imaginary, then w = -w_bar
|z|^2 = z * z_bar
1/z = z_bar if |z|=1
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📋 Question Details
- Chapter
- Complex Numbers
- Topic
- Properties of purely imaginary numbers
- Year
- 2014
- Shift
- 12 Apr Online
- Q Number
- Q62
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 5: Complex Numbers and Quadratic Equations
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