Equation solving

Equation solving - Basic info - Messages

#1 Posted: 5/15/2021 3:35:53 PM
Mateusz

Mateusz

0 likes in 8 posts.

Group: User

Hi,
First of all hello to all
I'am a new forum user as well as the SMath, too.
So: I have a question-> please see the below input deck (I don't know how to input png file :/ )

m:=850kg
G:=m*ge

L:=2.4m
LF:=1.3m
LR:=L-LF

solve(GFA*L=G*LR,GFA)

off course ge is the gravity. The above input don't give me solution. Could you help me??
I hope that attachment file will be correctly attached

test.sm (4 KiB) downloaded 32 time(s).

best regards,
Astroneus
#2 Posted: 5/15/2021 4:18:00 PM
overlord

overlord

552 likes in 1332 posts.

Group: Moderator

Wrote

Hi,
First of all hello to all
I'am a new forum user as well as the SMath, too.
So: I have a question-> please see the below input deck (I don't know how to input png file :/ )

m:=850kg
G:=m*ge

L:=2.4m
LF:=1.3m
LR:=L-LF

solve(GFA*L=G*LR,GFA)

off course ge is the gravity. The above input don't give me solution. Could you help me??
I hope that attachment file will be correctly attached

test.sm (4 KiB) downloaded 32 time(s).

best regards,
Astroneus


solve() calculates between -20/+20 unless different range is not specified.
This was your wrong doing here, result is way over 20. A well guessed range gives the result.
roots() must calculate without units like solve(), however you can fool functions by adding the unit of result.
Findroot() can calculate with unit but you have to give a starting guess value.

test_solve.sm (6 KiB) downloaded 32 time(s).

test_solve.png
#3 Posted: 5/15/2021 5:01:27 PM
Mateusz

Mateusz

0 likes in 8 posts.

Group: User

Wonderful !

Thankyou for quick reply. Answering to your question: I didn't use simple way due to learning purpose This was just simply example.

Btw. I installed the Maxima and I turn on the plugin in SMath. Could you tell me how to define the above equation for symbolic solution i.e. considering the GFa ???


Best regards,
Astroneus
#4 Posted: 5/15/2021 6:44:10 PM
overlord

overlord

552 likes in 1332 posts.

Group: Moderator

Wrote

Wonderful !

Thankyou for quick reply. Answering to your question: I didn't use simple way due to learning purpose This was just simply example.

Btw. I installed the Maxima and I turn on the plugin in SMath. Could you tell me how to define the above equation for symbolic solution i.e. considering the GFa ???


Best regards,
Astroneus


I use linux, maxima plugin doesn't work for us. Can't show you as smath example.
However I have maxima as cli and it can solve your function
Maple plugin can solve as you asked too if optimization is set to symbolic.
The idea is same, way of doing it and result shouldn't differ on maxima plugin.

Regards

2021-05-16_00-38_1.png
#5 Posted: 5/15/2021 7:18:01 PM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

992 likes in 1674 posts.

Group: User

Wrote

...
Btw. I installed the Maxima and I turn on the plugin in SMath. Could you tell me how to define the above equation for symbolic solution i.e. considering the GFa ???
...



Mi Astroneus. If you have Maxima, you can use Solve(). For learn about it (and a lot of things about Maxima and SMath) you can download the "Interactive SMath Handbook" by M. Kraska. Under Tools menu choose the interactive books option. If you don't have it, try to change "Local storage" to "Online gallery". The you can open it. Solve it's under Mathematics / Solving Non-Linear Equations / Solve.

Clipboard01.jpg

Best regards.
Alvaro.
#6 Posted: 5/15/2021 9:02:37 PM
overlord

overlord

552 likes in 1332 posts.

Group: Moderator

Wrote

If you have Maxima, you can use Solve().


Alvaro is right (like always), I have totally forgot maxima plugins's Solve() function cause I am not using windows for daily basis in a looong time.
There are also solvers like al_nleqsolve() or others in solving libraries/ plugins. You can find necessary informations for them in Reference Book, as Alvaro already mentioned.
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Alvaro Diaz Falconi 5/16/2021 9:45:00 PM
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