sc maths help (1 Viewer)

[want2beasenior]

We were told that we can't actually like study for maths as such with note making etc: the only way you can revise is by doing past papers. the content isn't hard but its the layout and the wording which screws people because what you actually learn in class doesn't really help you for school certificate because most of the content is 'general knowledge'

 

[tacogym27101990]

http://en.wikipedia.org/wiki/Imaginary_unit#i_and_.E2.88.92i

If you put i=-sqrt(-1), then i² would still be -1 wouldn't it?

well then why cant you assume sqrt(5)=-sqrt(5)??
you square both of them you still get 5

 

[Continuum]

well then why cant you assume sqrt(5)=-sqrt(5)??
you square both of them you still get 5

Quote from wikipedia article:

This is because, although −i and i are not quantitatively equivalent (they are negatives of each other), there is no qualitative difference between i and −i (which cannot be said for −1 and +1). Both imaginary numbers have equal claim to being the number whose square is −1.

 

[tommykins]

You cannot compare the magnitudes of complex numbers.