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#1 2013-04-27 00:51:28

elhamid
New Scratcher
Registered: 2013-04-24
Posts: 1

help with formula

i am new in scratch so how do i do i write down this formula in scribble


dlon = lon2 - lon1
dlat = lat2 - lat1
a = sin(dlat/2)*sin(dlat/2) + cos(lat1) * cos(lat2) * sin(dlon/2)*sin(dlon/2)
c = 2 * asin(sqrt(a)))
d = R * c

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#2 2013-04-28 02:31:55

Rikihiro
New Scratcher
Registered: 2013-04-24
Posts: 7

Re: help with formula

I'm not a mathematician, but I believe you have to setup a Variable for each element of your formula and give them their initial state of value. Then use the operators to finalize your formula.

Hope this was helpful.

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#3 2013-04-29 13:21:55

cauzality
New Scratcher
Registered: 2013-03-19
Posts: 44

Re: help with formula

like rikihero said

instead of " = ", use

set 
dlon ▼
 to 
lon2
 - 
lon1

i believe all your trig functions should be in the operators "drawer". drag in 
abs ▼
 of 
10

and select your function from the drop down menu

this will end up looking something like this:
when 
space ▼
 key pressed
set 
halfdlong ▼
 to 
lon2
 - 
lon1
/
2
set 
halfdlat ▼
 to 
lat2
 - 
lat1
/
2
set 
a ▼
 to 
sin ▼
 of 
halfdlat
*
sin ▼
 of 
halfdlat
+
cos ▼
 of 
lat1
*
cos ▼
 of 
lat2
*
sin ▼
 of 
halfdlong
*
sin ▼
 of 
halfdlong
set 
d ▼
 to 
2
 * 
R
 * 
asin ▼
 of 
sqrt ▼
 of 
a

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