Question

Is this correct ? Is this final result ?

Answer 1

no

Answer 2

look at the denominator (2-i)(2+i) = 4 -2i +2i -i^2 = 4 + 1 = 5

Answer 3

as a sanity check, remember that when you mult by the complex conjugate you get a real number.

Answer 4

Thanks Coolsector. Stupid mistake :/ So the result is 4i - 3 right ? Could you write it phi little bit comprehensibly ? I'am not good at english.

Answer 5

(a-bi)(a+bi) = a^2 + b^2 -> real number

Answer 6

4i - 3 -> correct!

Answer 7

So everytime when i modify complex number with "formula" i should get real number right ? This is my check right ?

Answer 8

everytime you multiply complex with a the corresponding conjugate :
(complex) * (conjugate complex) = real number

Answer 9

"a the" should be only "the"

Answer 10

Ok, i understand it little bit .. Thanks a lot

Answer 11

yw