[sdiy] Wave terrain synthesis (was Re: Generatingacyclicwaveforms?)

[cheater cheater]

> And, I know that in the
> unlikely event that I actually need it, I can read all about it in Chapter 1
> of the CRC ("rubber") Handbook sitting over there on my bookshelf...

And that's all you really need :-) The CRC books are fun, I suggest
Schaum too, they're real easy reads! BTW, reflection is easy... just
bend the piece of paper in half and pierce through where the vertices
are - instant reflection :-) Or constructively using the edge and
compass: make lines that go through each vertex and are perpendicular
to the axis of reflection. Or analytically: find the orthonormal
vector n for your axis of reflection L, and for the point p you want
to mirror create v = p+an, and plug v into your favorite formula for
L, and solve for a, then p+2an is your mirror image.

Now I feel the urge to think of applications of the determinant for
music composition or sound synthesis and come up with something so fun
that everyone will need it... ;-)

D.

On Tue, Apr 6, 2010 at 19:02, David G. Dixon <dixon at interchange.ubc.ca> wrote:
>> Huh?
>>
>> Why resurrect a 2 week old thread for something like this? You could
>> have written me offline..
>
> I concur.
>
> By the way, my 15-year-old daughter is learning how to reflect shapes across
> vertical and horizontal lines for Grade 9 Math, so I thought I'd "help" her
> by showing her how to generalize the process for any line of reflection.  Of
> course, I didn't really know how to do this, but I figured it would be easy
> to figure it out using simple algebra.  Well, after 30 minutes of trying,
> and then coming to the conclusion (probably mistaken) that I'd need
> trigonometry to do it, I gave up.
>
> Conclusion: the perfesser don't know no analytic geometry!  I never learned
> 1/2 as much analytic geometry as Ian Fritz has forgotten, or 1/4 as much as
> cheater remembers...  Of course, I've never actually had to apply it, which
> is probably why I never bothered to learn it.  And, I know that in the
> unlikely event that I actually need it, I can read all about it in Chapter 1
> of the CRC ("rubber") Handbook sitting over there on my bookshelf...
>
>