Question

subject: maths
class: 11

please answer this
​

Answer 1

Answer:

Step-by-step explanation:

Let a = 1, b = i

So the given expression is of form (a+b)³ - (a-b)³  

We know that

(a+b)³ = a³ + b³ + 3a²b + 3ab²

(a-b)³ = a³ - b³ - 3a²b + 3ab²

(a+b)³ - (a-b)³

= a³ + b³ +  3a²b + 3ab² - (a³ - b³ - 3a²b + 3ab²)

= a³ + b³ +  3a²b + 3ab² - a³ + b³ + 3a²b - 3ab²

= 2b³ + 6a²b

Substituting values of a and b,

= 2(i)³ + 6(1)²(i)

= -2i + 6i     (∵ i² = -1)

= 4i

= 0 + 4i