Q15 of 153 Page 13

If a = cos θ + i sin θ, find the value of

Given:

⇒ a=cosθ+isinθ

⇒

We know that 1+cos2θ=2cos²θ, 1-cos2θ=2sin²θ and sin2θ=2sinθcosθ

⇒

We know that i²=-1

⇒

∴ The value of is

If find x + y.

If find (a, b).

Evaluate the following :

2x³ + 2x² – 7x + 72, when

Evaluate the following :

x⁴ – 4x³ + 4x² + 8x + 44, when x = 3 + 2i