WB JEE 2011 | Complex Numbers Question 14 | Mathematics

PREVIOUS NEXT

WB JEE 2011

MCQ (Single Correct Answer)

-0.25

If $$x + {1 \over x} = 2\cos \theta $$, then for any integer n, $${x^n} + {1 \over {{x^n}}} = $$

$$2\cos n\theta $$

$$2\sin n\theta $$

$$2i\cos n\theta $$

$$2i\sin n\theta $$

WB JEE 2011

MCQ (Single Correct Answer)

-0.25

If $$\omega$$ $$\ne$$ 1 is a cube root of unity, then the sum of the series $$S = 1 + 2\omega + 3{\omega ^2} + \,\,.....\,\, + 3n{\omega ^{3n - 1}}$$ is

$${{3n} \over {\omega - 1}}$$

$$3n(\omega - 1)$$

$${{\omega - 1} \over {3n}}$$

WB JEE 2023

MCQ (Single Correct Answer)

-0.25

If the vertices of a square are $${z_1},{z_2},{z_3}$$ and $${z_4}$$ taken in the anti-clockwise order, then $${z_3} = $$

$$ - i{z_1} - (1 + i){z_2}$$

$${z_1} - (1 + i){z_2}$$

$${z_1} + (1 + i){z_2}$$

$$ - i{z_1} + (1 + i){z_2}$$

WB JEE 2023

MCQ (Single Correct Answer)

-0.25

Reflection of the line $$\overline a z + a\overline z = 0$$ in the real axis is given by :

$$az + \overline {az} = 0$$

$$\overline a z - a\overline z = 0$$

$$az - \overline {az} = 0$$

$${a \over z} + {{\overline a } \over z} = 0$$

PREVIOUS NEXT

WB JEE Subjects