CHAP, v.] EXAMPLES OF IRREGULAR PLOTTING 



137 



(4) .-. 



a . cos H 



cot Q + 



a . sin H h , cos G 



sin B sin B sin C 



Again, from (2) and (3) 



sin D . sin (/ + F sin B . sin 



sin E , sin ^ _ A sin C . sin <^ 



sin D (sin Q . cos F + cos Q . sin F) 



cot 4- 



h . sin G 

 sin C 



(5) 



sin B . sin 

 sin E (sin ^ .cos A — cos <^ . sin A) sin C . sin ^* 



sin D . cos F sin D . sin F 



sin B 



+ • 



. cot = 



sin B 

 sin E . cos A sin E ^Sin A 



sin C 



a . cos H 



= h 



m 



sin C 

 a . sin H 



cot ^ 



sin B 

 6 . sin G 



= 1 



sin C 

 sin D . sin F 



sin B 

 sin E . sin A 



= n 



= V 



sin C 



sin C 



= r 



Substituting in equations (4) and (5) respectively 



{%) h .cote +l = rn . Got 4) +n\ 



)' , „ i . - To obtain cot B and cot <f). 



{!) o+p . QotQ = q — r . cot <i> j ^ 



h . cot +l = in . cot <f) +no + p . cot B = q — r . cot (f> 

 m . cot 4> +n — l p {m . cot xn — l) 



(8) cot 8 



h 



h 



q—r . cot ^ 



o .h+p .m . cot(f) +n .p—p .1 

 = qh — rh . cot (f) 



q h—o h—n p +p I 



(9) .-. cot<^ = 



pm+rh 



The angles ^ and Q being obtained from the equations (9) 

 and (8) respectively, we have the mercatorial bearings of 



