*31 3 
46 
MINUTES OF PROCEEDINGS OF 
Now, this error will be greatest when cos ^ is least; that is, when 
= 100, its greatest value. Taking BC = 40 yds. ^-=100, we have 
e = 1*31 yds., which is not sufficient to affect our elevation. 
Tor our greatest error in defect we have 
e = BK — AB> 
_ BO_ _ 1 BC 
~~ sin a 2 . a 
sm- 
2 
BO 
2 
BC 
2 
cos l “ cos2 l 
1 1 — cos | 
cos ^ 1 + cos i 
This also is greatest when ^ — 100. 
Taking BC = 40 yds. = 100, we have e = *44 yds., which is not suffi¬ 
cient to affect our elevation. 
We now proceed to consider the second cause of error. 
In solving an isosceles triangle of known base and apex, the formula to 
use is 
r 
sill a 
Instead of this, we made sin - - = 1, and used the formula 
2 
h 
sm a 
This will give us an error, 
e = 5 “ 2sin|) 
i a 
l-cos- 
cos 
a 1 „ a 
W 1 - 0032 ! 
_b jl _ Z 1 - 003 ! 
” 2 'cos“' l +«»£ 
