An imagine Number,when squared, provides a negative result.

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Let"s shot squaring some numbers to check out if we can obtain a negative result:

No luck! constantly positive, or zero.

It seems like we cannot multiply a number by itself to get a an unfavorable answer ...


... Yet imagine the there is such a number (call it i for imaginary) that could do this:

Would it be useful, and what could we perform with it?

Well, by taking the square root of both political parties we obtain this:

Which way that ns is the answer come the square root of −1.

Which is actually an extremely useful because ...

... By just accepting that i exists we can solve thingsthat require the square source of a an unfavorable number.

Hey! the was interesting! The square source of −9 is merely the square root of +9, times i.

In general:

So lengthy as we keep that little "i" over there to remind united state that us stillneed to multiply by √−1 we space safe to proceed with our solution!

Using i

Interesting! We used an imaginary number (5i) and also ended up through a actual solution (−25).

Imaginary number can aid us deal with some equations:

Example: fix x2 + 1 = 0

Using actual Numbers there is no solution, but now us can fix it!

Subtract 1 indigenous both sides:

Answer: x = −i or +i


(−i)2 + 1 = (−i)(−i) + 1 = +i2 + 1 = −1 + 1 = 0(+i)2 +1 = (+i)(+i) +1 = +i2 +1 = −1 + 1 = 0


Unit imagine Number

The square root of minus one √(−1) is the "unit" imagine Number, the identical of 1 for actual Numbers.

In mathematics the symbol for√(−1) is i for imaginary.

Can you take the square root of −1?Well i can!

But in electronic devices they usage j (because "i" already way current, and also the following letter after ns is j).

Examples of imaginary Numbers

Imaginary Numbers room not "Imaginary"

Imaginary number were once thought to it is in impossible, and so lock were referred to as "Imaginary" (to make funny of them).

But then civilization researched them more and discovered they were in reality useful and also important since they fill a space in mathematics ... However the "imaginary" name has stuck.

And the is likewise how the surname "Real Numbers" came around (real is no imaginary).

Imaginary Numbers room Useful


Complex Numbers

Imaginary numbers become most helpful when merged with genuine numbers come make complicated numbers prefer 3+5i or 6−4i

Spectrum Analyzer


Those cool screens you see when music is playing? Yep, complicated Numbers are offered to calculate them! utilizing something dubbed "Fourier Transforms".

In fact countless clever things deserve to be done with sound using facility Numbers, like filtering out sounds, hear whispers in a crowd and also so on.

It is component of a subject referred to as "Signal Processing".



AC (Alternating Current) electricity changes in between positive and an unfavorable in a sine wave.

When we combine two AC currents they may not enhance properly, and it can be an extremely hard to figure out the new current.

But using complicated numbers renders it a lot simpler to do the calculations.

And the an outcome may have actually "Imaginary" current, however it have the right to still pains you!


Mandelbrot Set

The beautiful Mandelbrot collection (part of that is pictured here) is based on complicated Numbers.

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Quadratic Equation


The Quadratic Equation, i m sorry has many uses,can offer results that incorporate imaginary numbers

Also Science, Quantum mechanics and also Relativity use complex numbers.

Interesting Property

The Unit imagine Number, i, has an exciting property. That "cycles" through 4 different values each time we multiply:

1 × i= i
i × i= −1
−1 × i= −i
i × i= 1
Back to 1 again!

So we have actually this:

i = √−1i2 = −1i3 = −√−1i4 = +1
i5 = √−1i6 = −1...etc

Example What is i10 ?

i10= i4 × i4 × i2
= 1 × 1 × −1
= −1

And that leads us into an additional topic, the complicated plane: