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Student Support Forum: 'getting wrong answer for system of two equations' topicStudent Support Forum > General > Archives > "getting wrong answer for system of two equations"

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Brett
06/08/13 09:34am

I tried to solve the following with Mathematica, but it seems to give me some screwy answers that don't agree with what I get by hand. Here' the code:

Solve[{v1 == -2 v2, 24 u^2/9 + 3 e/(2 m) == v1^2 + 2 v2^2}, {v1, v2}]

output:

v1 -> -((I Sqrt[-9 e - 16 m u^2])/(3 Sqrt[m])),
v2 -> (I Sqrt[-9 e - 16 m u^2])/(6 Sqrt[m])},

{v1 -> (I Sqrt[-9 e - 16 m u^2])/(3 Sqrt[m]),
v2 -> -((I Sqrt[-9 e - 16 m u^2])/(6 Sqrt[m]))

I guess "I" means imaginary number. By hand I get
v2 -> +-Sqrt[4 u^2 + e/(4 m)]
v1 -> -2 v2

What's going on? I quit the kernal several times.
thanks

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Subject (listing for 'getting wrong answer for system of two equations')
Author Date Posted
getting wrong answer for system of two equations Brett 06/08/13 09:34am
Re: getting wrong answer for system of two equa... Forum Modera... 06/08/13 6:16pm
Re: Re: getting wrong answer for system of two ... Brett 06/09/13 02:57am
Re: Re: Re: getting wrong answer for system of ... Forum Modera... 06/09/13 1:31pm
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