Question

which expression represents purely real numbers and which expression represents non-real complex number?​

Answer 1

Answer:

Step-by-step explanation:

Complex numbers are the numbers represented by the expression = a + bi

Here a = real part of the number

bi = imaginary part

a and b are the real numbers.

$i^9=(i^2)^4.(i)$

    $=(-1)^{4}.i$ [Since, $i^2=-1$]

    $=i$

Therefore, its a non real complex number.

2 - $\sqrt{-49}$ = $2-\sqrt{(-1)(7)^2}$

               = $2-7\sqrt{-1}$

               = $2-7i$

This number is a Non real complex number.

$\sqrt{(-18)^2}=18\sqrt{-1}$

              = 18i

It's a non real complex number.

3 + 2i

It's a non real complex number.

-289

It's a purely real number.

$4-32i^2=4-32(-1)$

             = 4 + 32

             = 36

It's a purely real number.