Help with imaginary and complex numbers

AI Thread Summary
Imaginary numbers involve the unit "i," defined as the square root of -1, while complex numbers combine a real part and an imaginary part in the form a + bi. For instance, 3i is an imaginary number, and 2 + 4i is a complex number. Basic operations include adding or subtracting by combining real and imaginary parts separately, and multiplying using the FOIL method, remembering that i² equals -1. Division requires rationalizing the denominator by multiplying by the conjugate. Understanding these concepts can significantly aid in completing homework and grasping the subject better.
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If someone could give me some notes explaining about them that i could follow so i can do my homework and stuff it would be appreciated! I don't understand them at the moment b/c i don't understand the teacher, which is definately my problem. So it would be nice if i could get an explanation that i can understand!
 
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Sure, no problem! Imaginary and complex numbers can be a bit confusing at first, but with some practice and explanation, you'll be able to understand them.

First, let's start with imaginary numbers. These are numbers that involve the imaginary unit, denoted by "i". This unit is defined as the square root of -1. So, whenever you see "i" in a number, you know it represents the square root of -1.

For example, the number 3i is an imaginary number because it has the imaginary unit "i" in it. Another example is -5i, because it also has the imaginary unit "i" in it.

Now, let's move on to complex numbers. These are numbers that involve both a real part and an imaginary part. They are written in the form a + bi, where a is the real part and bi is the imaginary part. The letter "a" represents a real number, and "b" represents a coefficient that is multiplied by the imaginary unit "i".

For example, the number 2 + 4i is a complex number because it has both a real part (2) and an imaginary part (4i). Another example is -3 + 7i, because it also has both a real part (-3) and an imaginary part (7i).

Now, let's talk about some basic operations with imaginary and complex numbers.

1. Addition and Subtraction: When adding or subtracting imaginary or complex numbers, you simply combine the real parts and the imaginary parts separately. For example, (3 + 2i) + (5 + 3i) = 8 + 5i.

2. Multiplication: When multiplying imaginary or complex numbers, you use the FOIL method, just like you would with binomials. For example, (3 + 2i)(5 + 3i) = 15 + 9i + 10i + 6i^2. Remember that i^2 = -1, so this simplifies to 15 + 19i - 6 = 9 + 19i.

3. Division: To divide imaginary or complex numbers, you need to rationalize the denominator. This means getting rid of any imaginary units in the denominator. To do this, you multiply the numerator and denominator by the conjugate of the denominator. The conjugate of a + bi is
 
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