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Thought-Process to Discover Knowledge

Welcome to nubtrek.

Books and other education websites provide "matter-of-fact" knowledge. Instead, nubtrek provides a thought-process to discover knowledge.

In each of the topic, the outline of the thought-process, for that topic, is provided for learners and educators.

Read in the blogs more about the unique learning experience at nubtrek.
mathsComplex NumbersProperties of Complex Number Arithmetic

### Addition : Commutative Law

Complex addition is commutative : Complex numbers can be swapped in complex addition.

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What does 'commute' mean? • to go to and fro on a regular basis
• to go to and fro on a regular basis
• It is not an English word.

The answer is 'to go to and fro between two places on a regular basis'.

Consider the addition and subtraction of complex numbers. z_3 = z_1+z_2 given as a_3+ib_3 = (a_1+a_2)+i(b_1+b_2), where a_1, a_2, b_1, b_2 in RR.

Will z_1+z_2 = z_2+z_1? • Yes, the real and imaginary part addition is nothing but real number addition.
• Yes, the real and imaginary part addition is nothing but real number addition.
• No. The properties of complex numbers need to be studied to understand.

The answer is 'Yes, the real and imaginary part addition is nothing but real-number addition.'.

•  Complex numbers can be swapped in complex addition - commutative.

Commutative Property of Complex addition: for any complex number z_1, z_2 in CC
z_1 + z_2 = z_2 + z_1

Is commutative property defined for complex subtraction?

• No. The properties are not defined for inverse operations.
• No. The properties are not defined for inverse operations.
• Yes. The properties are defined for subtraction too

The answer is 'No. The properties are not defined for inverse operations.' Subtraction is the inverse of addition.

Subtraction is the inverse of addition.

The commutative property has to be used in the following way.
z_1-z_2
quad quad = z_1 + (-z_2)
quad quad =(-z_2) + z_1 (commutative property of addition.)

Solved Exercise Problem:

Given two complex numbers z_1, z_2; z_1+z_2 = 3.1+i2.9. Find the value of z_2+z_1.

• 3.1+i2.9
• 3.1+i2.9
• 3.1-i2.9
• -3.1+i2.9
• 2.9+i3.1

The answer is '3.1+i2.9'

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