- #1

ItsKP

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## Homework Statement

Given: x (dot) y = x^T * y (where x,y are vectors; dot is dot product; and x^T is x transpose)

and R is an orthogonal nxn matrix, and x,y are elements of R^n

Show ||Rx|| = ||x||

## The Attempt at a Solution

I'm not sure what information I am suppose to use to solve this. This is what I have gathered so far:

x(dot)y = x1y1 + x2y2+ ... + xnyn = x^T * y

But how am I suppose to use any of this to solve the problem? Is it involving inner products at all?