Re: distance from Easter Island to Chile

[giacomo . boffi]

Emanuel Berg <embe8573@student.uu.se> writes:

> Frank Stutzman <stutzman@cat2.kjsl.com> writes:
>
>> I get an answer of 4301.199 

mee too

> That's normal

(progn 
  (defun d2r (x) (/ (* pi x) 180))
  (defun spherical-law-of-cosines (p1 p2)
    "http://en.wikipedia.org/wiki/Great-circle_distance#Formulas";
    (let ((lat1 (car p1)) (lon1 (cadr p1))
          (lat2 (car p2)) (lon2 (cadr p2)))
      (acos (+ (* (sin lat1) (sin lat2))
               (* (cos lat1) (cos lat2) (cos (- lon2 lon1)))))))
  
  (setq santiago (mapcar 'd2r '(33.4500  70.6667)))
  (setq easter_i (mapcar 'd2r '(27.1167 109.3667)))
  (insert (format "\nEaster Island to Santiago distance is%8.2f km."
                  (* (spherical-law-of-cosines santiago easter_i) 6378.1))))
                                                                            ^
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