March 2nd, 2017, 06:31 PM  #11 
Newbie Joined: Mar 2017 From: United States Posts: 8 Thanks: 0 
Hi skipjack, That's a very good lead and useful information. Let me play around with that a little and I'll let you know the results of what I find!!! 
March 3rd, 2017, 02:33 AM  #12 
Senior Member Joined: Apr 2014 From: Glasgow Posts: 1,884 Thanks: 610 Math Focus: Physics, mathematical modelling, numerical and computational solutions 
That's a good spot SkipJack! So basically the function seems to behave something like $\displaystyle f(x) = x/45  tan x$ but if the tan x evaluates to infinity, it just sets it to zero. Can you try working out the function with angles of 60, 65 and 70 (starting from a 'value' of zero) and see if you get 0.23208, 0.5195 and 1.1919? 
March 9th, 2017, 12:36 PM  #13 
Newbie Joined: Mar 2017 From: United States Posts: 8 Thanks: 0  
March 10th, 2017, 09:24 PM  #14 
Newbie Joined: Mar 2017 From: United States Posts: 8 Thanks: 0 
I'm needing to find a formula that will allow me to calculate values around the circumference of a static size circle. The table below describes the circle size and the values around the circumference every 22.5 degrees apart. With the help from skipjack I was able to create these formulas that match my software values: Start...Degrees.....Result...........Formula...... .........Formula 0.............0.............0...................0. ........................0 0..........22.5......0.414214...... sqrt(2)  1.............tan(22.5) 0............45..........1...................sqrt( 1)................tan(45) 0..........67.5......1.585786.......3  sqrt(2)........2  tan(22.5) 0........... 90..........2..............sqrt(1) + 1..........tan(45) + 1 0........112.5......2.414214......1 + sqrt(2).......tan(22.5) + 2 0..........135..........3..............sqrt(1) + 2..........tan(45) + 2 0........157.5......3.585786.......5  sqrt(2)........4  tan(22.5) 0..........180..........4..............sqrt(1) + 3..........tan(45) + 3 0........202.5......4.414214.......3 + sqrt(2)..... tan(22.5) + 4 0..........225..........5..............sqrt(1) + 4......... tan(45) + 4 0........247.5......5.585786.......7  sqrt(2)........6  tan(22.5) 0..........270..........6..............sqrt(1) + 5..........tan(45) + 5 0....... 292.5......6.414214.......5 + sqrt(2)......tan(22.5) + 6 0..........315..........7..............sqrt(1) + 6......... tan(45) + 6 0........337.5......7.585786.......9  sqrt(2)........8  tan(22.5) 0..........360..........8..............sqrt(1) + 7..........tan(45) + 7 What I can't figure out is how to calculate other 22.5 degree values by starting at a point other than zero. Here are some random starting points with the answer from a software program but I need a formula to show me how that answer was obtained: Starting at 2.1 and travel 22.5 degrees returns a value of 2.536433 Starting at 2.1 and travel 67.5 degrees returns a value of 3.698284 Starting at 3.5 and travel 22.5 degrees returns a value of 3.928932 Starting at 3.5 and travel 67.5 degrees returns a value of 4.867295 Again, thanks for any help. 
March 12th, 2017, 01:15 PM  #15 
Global Moderator Joined: Dec 2006 Posts: 16,595 Thanks: 1199 
Can you give some additional values based on starting at values less obscure than 2.1 and 3.5?

March 12th, 2017, 01:24 PM  #16 
Newbie Joined: Mar 2017 From: United States Posts: 8 Thanks: 0  I should be able to provide any starting point with the answer using the software with any number between 2  10. Please give me a list of numbers you want.
Last edited by Frankenstein2; March 12th, 2017 at 01:26 PM. 
March 12th, 2017, 01:55 PM  #17 
Senior Member Joined: Jun 2015 From: England Posts: 509 Thanks: 130 
Could this program have anything to do with Mohr Circles, which are often offset from the origin? https://www.google.co.uk/search?hl=e...85.FfsaG8peeUY 
March 12th, 2017, 02:16 PM  #18 
Global Moderator Joined: Dec 2006 Posts: 16,595 Thanks: 1199  Try a starting value of 7.5.
Last edited by skipjack; March 12th, 2017 at 03:59 PM. 
March 12th, 2017, 02:37 PM  #19  
Newbie Joined: Mar 2017 From: United States Posts: 8 Thanks: 0  Quote: Starting at 7.5 and travel 22.5 degrees BACKWARD returns a value of 6.867295 Starting at 7.5 and travel 45 degrees FORWARD returns a value of 8.333333 Starting at 7.5 and travel 45 degrees BACKWARD returns a value of 6.333333 Starting at 7.5 and travel 67.5 degrees FORWARD returns a value of 8.867295 Starting at 7.5 and travel 67.5 degrees BACKWARD returns a value of 5.928932 Starting at 7.5 and travel 90 degrees FORWARD returns a value of 9.5 Starting at 7.5 and travel 90 degrees BACKWARD returns a value of 5.5 Last edited by skipjack; March 12th, 2017 at 03:59 PM.  

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