Sorry, I did not mean you were not clear to each other. Just that a
few comments can help follow.
Like:
The connection between ∏ and arctan is that arctan (1) is ∏ divided by 4
arctan=:_3&o.
arctan 1
0.785398
1p1%4
0.785398
Donna
[EMAIL PROTECTED]
On 30-Jun-06, at 7:05 PM, John Randall wrote:
dly wrote:
It is just clearer when you know what arc tan is and then why it
relates
just briefly in between the J
Donna:
I thought this explanation was pretty clear:
[snip]
arctan=:_3&o.
angle =:12&o.
For real y, arctan y is the angle between _1r2p1 and 1r2p1 whose
tangent
is y.
For real x and y, angle x+j.y is the angle from the x-axis to (x,y),
between _1p1 and 1p1.
If x>0, arctan y%x is the same as angle x+j.y, but not if x<:0.
[/snip]
There is some J in it, but then this is a J group. Someone who
uses J's
o. functions can be assumed to know something about complex numbers
and
their representation as the Argand diagram. I know what orthogonal
vectors are: I just did not think it relevant to mention them, and
I have
to assume some context.
Again, please feel free to write up something if you think this is
unclear
or presuming too much.
Best wishes,
John
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