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## Homework Statement

Question is when

F(s) = ## \frac {(s)^2+2*ζa*Wn*s+(Wn)^2)} {(s)^2+2*ζb*Wn*s+(Wn)^2)} \ ##

prove that ## \ {|F(iw)|}^2 \ ## = 1 - ## \frac {4(ζb^2-ζa^2) \tilde w} {(1-\tilde w)^2+4ζb^2 \tilde w} \ ##

when ## \tilde w \ ## = ## (\frac {w} {Wn} )^2 \ ##

## Homework Equations

F(s) is the equation of a notch filter. |F(iw)| is the magnitude of its frequency response.

## The Attempt at a Solution

I have replaced s by iw in the F(s) equation but ended up with something weird which doesn't make sense. Can someone please help!