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Solving system of equations gives empty output, but gives result when reduced

Panron Ryan
Posted 10 years ago

I want solve equation group below, but you can see the result return a {}, but when i reduce the equation group like this , it can give a solution(Seeing in the image), why is this ? enter image description here
POSTED BY: Panron Ryan
6 Replies
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Five equations in three unknowns, you are asking for trouble. However, you get solvability conditions in terms of the parameters:

eqs = {fn1*Sin[a] - fn2*Sin[a] == 0,
   fn3 + 2 fn1*Cos[a] - f == 0,
   dl1 == dl3*Cos[a],
   dl1 == fn1*1/(e1*a1*Cos[a]),
   dl3 == fn3*1/(e3*a3)};
vars = {fn1, fn2, fn3};
sol0 = Solve[eqs[[{1, 2, 4}]], vars]
eqs /. sol0[[1]]
Solve[eqs /. sol0[[1]]]
POSTED BY: Gianluca Gorni

Try it with a space or a * between a and x and between b and y, etc.

But if you want ax to be a single variable and not the product of a and x, then I have no idea what you wanted to ask. It would be helpful if you included a question that could be answered.

In future, I think it would be better to start a new discussion to discuss a new problem. I wouldn't introduce a new problem into an old discussion.
POSTED BY: Michael Rogers
ZHONG YAN
ZHONG YAN
Posted 2 months ago

enter image description here
POSTED BY: ZHONG YAN
Panron Ryan
Panron Ryan
Posted 10 years ago

I want solve equation group below, but you can see the result return a {}, but when i reduce the equation group like this , it can give a solution(Seeing in the image), why is this ? enter image description here
POSTED BY: Panron Ryan
David Keith
David Keith
Posted 10 years ago

Please put your code in code blocks, not as images. Code blocks allow other members to copy and paste your code into Mathematica. You can find out how to do that, and many more useful things, by reading How to post.
POSTED BY: David Keith
Okkes Dulgerci
Okkes Dulgerci
Posted 10 years ago

you have two Delta_l1
POSTED BY: Okkes Dulgerci
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