NCERT Exemplar Solutions
Class 11 - Mathematics - Chapter 5: COMPLEX NUMBERS AND QUADRATIC EQUATIONS
Fill in the Blanks

Question. 25(i)

(i) For any two complex numbers \(z_1, z_2\) and any real numbers \(a, b\), \(\; |az_1 - bz_2|^2 + |bz_1 + az_2|^2 = ____\).

Answer:

\((a^2 + b^2)\bigl(|z_1|^2 + |z_2|^2\bigr)\)

Question. 25(ii)

(ii) The value of \(\sqrt{-25} \times \sqrt{-9}\) is ____.

Answer:

-15

Question. 25(iii)

(iii) The number \(\dfrac{(1 - i)^3}{1 - i^3}\) is equal to ____.

Answer:

-2

Question. 25(iv)

(iv) The sum of the series \(i + i^2 + i^3 + \dots\) up to 100 terms is ____.

Answer:

0

Question. 25(v)

(v) The multiplicative inverse of \(1 + i\) is ____.

Answer:

\(\dfrac{1}{2} - \dfrac{i}{2}\)

Question. 25(vi)

(vi) If \(z_1\) and \(z_2\) are complex numbers such that \(z_1 + z_2\) is a real number, then \(z_2 = ____\).

Answer:

\(\overline{z_1}\)

Question. 25(vii)

(vii) \(\arg(z) + \arg(\overline{z})\) \((\overline{z} \ne 0)\) is ____.

Answer:

0

Question. 25(viii)

(viii) If \(|z + 4| \le 3\), then the greatest and least values of \(|z + 1|\) are ____ and ____ respectively.

Answer:

6 and 0

Question. 25(ix)

(ix) If \(\left|\dfrac{z - 2}{z + 2}\right| = \dfrac{\pi}{6}\), then the locus of \(z\) is ____.

Answer:

a circle

Question. 25(x)

(x) If \(|z| = 4\) and \(\arg(z) = \dfrac{5\pi}{6}\), then \(z = ____\).

Answer:

\(-2\sqrt{3} + 2i\)

NCERT Exemplar Solutions Class 11 – Mathematics – Chapter 5: COMPLEX NUMBERS AND QUADRATIC EQUATIONS – Fill in the Blanks | Detailed Answers