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# imaginary number equation Watch

1. In physics, I have come across two equations for impedance:

where

Does this mean that from:

then

??

so is this an alternative form of pythag or am I completely wrong??
2. (Original post by Random999)
In physics, I have come across two equations for impedance:

where

Does this mean that from:

then

??

so is this an alternative form of pythag or am I completely wrong??
No, I think you've omitted some modulus signs around z like this: |z|
3. If z=x+iy (where x and y are both real), then |z|2=x2+y2. As davros says, you appear to have lost a modulus sign somewhere: in general, it is not the case that sqrt(a2+b2)=a+bi.
4. (Original post by Random999)
??
As above, though it may be worth noting that
In general:
Where then:

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