Question

 In complex number (1+2i)(-2+i) the value of real and imaginary part is​

Answer 1

Answer:

real part = - 4

imaginary part = - 3

Step-by-step explanation:

⇒ (1 + 2i)(-2 + i)

⇒ -2 + i - 4i + 2i²

⇒ -2 - 3i + 2(-1)       [i² = - 1]

⇒ -2 - 3i - 2

⇒ - 4 - 3i

∴ Re(-4 - 3i) = - 4

  Im(-4 -3i) = - 3

Answer 2

Given:

A number in the complex form (1+2i)(-2+i).

To Find:

The real and imaginary part after simplifying the equation is?

Solution:

The given number can be solved using the concepts of complex numbers.

1. The standard form of a complex number is a + ib.

2. The given complex form is (1+2i)(-2+i).

=> Simplify the above form,

=> 1*(-2) + 1*i + 2i*(-2) + 2i*i,

=>-2 + i - 4i + 2i², ( The value of i² is -1 )

=> -2 -3i + 2(-1),

=> -2 -3i -2,

=> -4 -3i.

3. a + ib = -4 - 3i,

=> a = real part = -4,

=> b = imaginary part = -3.

Therefore, the real part and the imaginary part of the given number are -4 and -3 respectively.