John Nolton
Posts: 15
Joined: 10/11/2011

Problem 284 New Solution is Incorrect 
Flag »
Reply »

The new solution to problem 284 posted by Shelly Cox yesterday (2/3/2014) is not correct.
It looks like the typo error and the ommision of "m" in Lindell's equation number [3] were corrected as per my 1st post but somebody DID NOT look at my 2nd post and they DID NOT read it very well.
I clearly state that Lindell's equation [3] is incorrect and if you solve it you will NOT get the answer Lindell shows. I give the solution to equation [3] as presented with the "m" in it and it is m = 39d 45m 10.1981s. Now if one will work the values of "m" as Lindell shows,
m = 30d , [3] yields +2.44615242 THIS IS NOT WHAT YOU WILL GET WHEN YOU USE 30d.
Nor will you get the values for 45d or 60d.
I found a on line program for plotting equations and when equation [3] is programmed in it it shows that the answer is very close to 0.7 radians which = 40d+.
Lindell does have the correct answer as I have stated and I give more places just for the heck of it. It would be nice to know what internet program Lindell used to reduce the equation just above his equation [3] because it clear he left something OUT of it in his presented solution.
In Mathematica the reduced equation is 2(1 + 2 Cos[m]) Cot[m] / 2 + 3 Sin [m] = Tan[m]. Solving this equation in Mathematica gives Lindell's final answer. I also solved Lindell's equation just above his equation [3] on my HP20s calculator and get the same answer as I get using Mathematica.
I hope I have helped all the people that read this great magazine with problem 284.
John Nolton
Tombstone, AZ.



Tuesday, February 04, 2014 at 10:24:30 AM 