109

be deducted from the index , because in thefollowing investigation the radius is made1, the logarithm of which is 0, whereas inthe table of logarithmic sines, tangents, &c.the logarithm of the radius is made 10.

By the different relations obtained in thisarticle we are furnished with sufficient datato solve the following :

9. Problem, wherein it is proposed tofind any four of the six quantities <p, c, t, z,x, and y, the remaining two being given.

CASE I.

When and c are given, to find the rest.

z — c tang. <p

t — c sec. <p

t . c ver.sin.A

x — c (sec.®—1) = -

v r ' cos. $

y ■=. c m log.tang. (45° —

CASE II.

When <p and t are given, to find the rest.

t

=t cos. <?

sec. $

Z =:

t sin. f

X =

t ver. sin. $

y —

wfcos.<plog.tang.(45 e -j-i , P)