Ed, > For instance, if angles are measured in degrees and x<<1 > sin x ~ pi * x / 180 > sin x ~ x
Your equations cannot simultaneously be true & in fact the 1st one is obviously wrong, the 2nd is right. In the 1st case I think you meant (substituting 'x*deg' for 'x' in your correct 2nd equation): sin(x*deg) ~ (x*deg) for (x*deg) << 1 where 'deg' = pi/180. Therefore we have: sin(x*deg) ~ pi*x/180 > There are many other examples of such agreements. For instance, the > singular choice of axes permutation in P21212 is to make sure that > two-fold is along c. We could agree instead to always have > a>b>c - it's > workable, but we would have to keep two more space groups > around (hope I > didn't make too many factual mistakes here). Just one: it's a<=b<=c. In any case, this comment is analogous to Henry Ford's famous sales pitch for the Model T: "You can have a car in any colour so long as it's black". Tell me, which would you say makes more sense: a) 1 person spends 10 secs adding 10 lines to the syminfo file once and for all, or b) many people post queries to CCP4BB about re-indexing their MTZ files because the processing mis-identified 2-fold screw axes from the systematic absences? > PS. By the way, did you notice that pi^2 ~ g ? I ... and did you notice that e^(i*pi) + 1 = 0 connects the 5 fundamental mathematical constants? - that also has nothing whatsoever to do with this thread ;-). Cheers -- Ian Disclaimer This communication is confidential and may contain privileged information intended solely for the named addressee(s). It may not be used or disclosed except for the purpose for which it has been sent. If you are not the intended recipient you must not review, use, disclose, copy, distribute or take any action in reliance upon it. If you have received this communication in error, please notify Astex Therapeutics Ltd by emailing i.tic...@astex-therapeutics.com and destroy all copies of the message and any attached documents. Astex Therapeutics Ltd monitors, controls and protects all its messaging traffic in compliance with its corporate email policy. The Company accepts no liability or responsibility for any onward transmission or use of emails and attachments having left the Astex Therapeutics domain. Unless expressly stated, opinions in this message are those of the individual sender and not of Astex Therapeutics Ltd. The recipient should check this email and any attachments for the presence of computer viruses. Astex Therapeutics Ltd accepts no liability for damage caused by any virus transmitted by this email. E-mail is susceptible to data corruption, interception, unauthorized amendment, and tampering, Astex Therapeutics Ltd only send and receive e-mails on the basis that the Company is not liable for any such alteration or any consequences thereof. Astex Therapeutics Ltd., Registered in England at 436 Cambridge Science Park, Cambridge CB4 0QA under number 3751674
