Teaser-5

[noodlz]

the sqare root of a negative number does not exist.

Yes it does.

divide the length of the edge of a cube by 12 and cube the answer. e.g. 48 divided by 12 equals 4. 4x4x4 equals 16.

WTF?

i think his middle name must begin with an 'f', BAS.

Disclaimer: The above reference was purely meant as a light-hearted joke without intention to discredit anyone's character. Any distress caused is deeply regretted and please accept this as a full apology, if this is the case.

 

[noseall]

the sqare root of a negative number does not exist.

Yes it does.

only in your imagination bas.

 

[ban-all-sheds]

Not just mine....

 

[noseall]

sorry...........

only in ones imagination.

 

[Spark123]

I don't quite follow, a number multiplied by itself can't equal a negative number, i.e. -ve*-ve = +ve, hence a negative number can't have a square root?
To find the area of a cube from its length do you not need to cube it?

 

[noseall]

i assumed the cube question meant the sum of the edge of the cube.

in other words all 12 edges.

hence divide by 12 and cube the answer.

i'd had a few stellas.

in maths, by multiplying two negatives you get a positive. so generally it can't exist. so maths boffins just make it up and call it an imaginary figure to "plug a hole".

 

[johnny_t]

I don't quite follow, a number multiplied by itself can't equal a negative number, i.e. -ve*-ve = +ve, hence a negative number can't have a square root?
To find the area of a cube from its length do you not need to cube it?

Quite correct, but for some mathematical fancy stuff, it is useful to have the concept of a square root of a negative number. This is then simplified down to a number of times the square root of -1, e.g the square root of -25 is equal to the square root of 25 (or 5) x the square root of -1. The square root of -1 is often written as i (hence the original question), j in electronics to avoid confusion with small signal currents. Any number that includes a portion using the square root of -1 is referred to as an imaginary number, hence noseall's statement above.

Been a long time since I've had to use it, so can't give any examples where it may be handy, unfortunately.....