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# Imaginary numbers watch

1. Hey this is a further maths topic MFP1 (AQA), could someone please explain this concept to me, as the textbook doesnt explain it very well.

Many thanks!!
2. Big topic - very small space.

Can you give us some idea what you are having trouble with? I have some Powerpoints I could send you if you like.
3. SQRT(-1) is not a real number ; -1 has no square root. Nothing squared is -1, because a double positive is positive, a double negative is positive and a positive + negative is negative, but not the same number.

therefore, SQRT(-1) is imaginary, and expressed as i.

imaginary numbers are expressed in the form a +bi ; for eg
3 + 3i

http://en.wikipedia.org/wiki/Imaginary_number

4. thats the basic concept... cant really go into much more detail without knowing what area you're having trouble with
5. (Original post by lubus)
SQRT(-1) is not a real number ; -1 has no square root. Nothing squared is -1, because a double positive is positive, a double negative is positive and a positive + negative is negative, but not the same number.

therefore, SQRT(-1) is imaginary, and expressed as i.

imaginary numbers are expressed in the form a +bi ; for eg
3 + 3i

http://en.wikipedia.org/wiki/Imaginary_number
Just to slghtly tweak this, COMPLEX numbers are written in the form a +ib where a is the real part and b is the imaginary term.

There are some basic rules when operating with complex numbers:
subtraction(very similar): (a+ib) - (c+id)= (a-c)+(b-d)i
multiplication: (a+ib) (c+id)= ac+adi+cbi+bdi^2, (remember i^2=-1)
Division: a bit tricky so look up the complex conjugate
6. (Original post by Mr M)
Big topic - very small space.

Can you give us some idea what you are having trouble with? I have some Powerpoints I could send you if you like.
Hey, yes please the powerpoints would be very useful- I've PM'ed you.

Cheers.
7. (Original post by didgeridoo12uk)

thats the basic concept... cant really go into much more detail without knowing what area you're having trouble with
OK.

I will read through the textbook again and outline my concerns.

Thanks

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