From: Sandy King ^lt;*[email protected]*>

Date: 08/08/04-08:05:30 PM Z

Message-id: <a0602040fbd3c8c6261c9@[192.168.2.4]>

Date: 08/08/04-08:05:30 PM Z

Message-id: <a0602040fbd3c8c6261c9@[192.168.2.4]>

Ryuji, and Loris,

Thanks for the reply. Based on your comments I can see the error I made.

Best,

Sandty

*>From: Sandy King <sanking@clemson.edu>
*

*>Subject: Circle of Confusion Question
*

*>Date: Sun, 08 Aug 2004 19:53:21 -0400
*

*>
*

*>> He provides the answer for this equation for a distance of 25 cm as a
*

*>> linear measurement of 0.07mm, or 70 microns, and continues by noting
*

*>> that the tangent of one minute of arc is roughly 0.00029. I have
*

*>> worked this problem backwards several ways and still have not been
*

*>> able to figure out how he determined that the tangent of one minute
*

*>> of arc is 0.00029.
*

*>
*

*>What did you get? If you got tan 0.0167 = 0.0167, I suppose your
*

*>calculator used radian as the unit of the angle while you assumed it
*

*>was degree. You need to change the calculator's setting, or convert
*

*>the unit before obtaining tangent. 180 degrees is exactly one pi
*

*>radian.
*

*>
*

*>For such a small value like 1/60 of a degree, tan x is practically x
*

*>where x is in radians. (That is, if alpha is the angle in degrees,
*

*>tan alpha is very close to alpha/57.3.) This is obvious if you obtain
*

*>Taylor series expansion of tan x around x = 0 (or Maclaurin
*

*>expansion).
*

*>
*

*>--
*

*>Ryuji Suzuki
*

*>"You have to realize that junk is not the problem in and of itself.
*

*>Junk is the symptom, not the problem."
*

*>(Bob Dylan 1971; source: No Direction Home by Robert Shelton)
*

Received on Mon Aug 9 12:18:20 2004

*
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