- #1

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## Homework Statement

S.T <f> is not normal. where f is a reflection

## Homework Equations

<f>={e,r^0 f, r^1f,r^2f,..}

WTS For any g in D-n, g(r^kf)g^-1 Not In <F>

## The Attempt at a Solution

Elements of D-n are r^k, r^kf

For r^k, (r^k)(r^if)(r^-k) is in <f>.

So I am stuck