However, due to complex number having 2 terms, namely, real and imaginary terms, care has to be taken for the "i"unit.

This is specially so when multiplication of

**conjugate**is involved.

A

**made while doing this form of multiplication is:**

__popular mistake__(3 + i2)(3 - i2) = 3

^{2}+ (i2)

^{2}

*What is wrong?*

The concept of conjugate and its multiplication states that:

(a + ib)(a - ib) = a

^{2}+ b

^{2}

The "i" symbol is NOT reflection in the final outcome!

Only the "a" and the "b", the numerical part, are extracted out for computation.

Taking the "i" into account will cause the sign of the last term (i2) to be incorrect.

This is because i

^{2}= -1.

Therefore, regardless of the sign in the multiplicands, just pull out the numerical part in the complex number and use them for calculation, that is, the 3 and 2 in the example above.

The

**correct answer**, thus, is (

**3**+ i

**2**)(

**3**- i

**2**) =

**3**

^{2}+

**2**

^{2}.

Looking carefully at the application of the formula, you will notice that this is a simple and easy technique to do conjugate multiplication.

Message: "Touch me not"

**said.**

*i**Mastery takes place when we do not repeat mistakes.*

.

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