My friends less expensive ti solves a 3x4 system of linear equations in terms of 4th unknown. How do i do this on my prime?

Example

2a+2b+2c=0

3a+b+2c=0

a+b+c=W

I want to get all my variables in terms of W. The type of problem im solving is a statics problem and im asked to find the maximum weight of flowerpot if the chain can hold a max 50lb tension. So W represents the maximum weight (flowerpot) that the system can hold. How do i input this?

(10-02-2016 05:26 PM)yland Wrote: [ -> ]2a+2b+2c=0

3a+b+2c=0

a+b+c=W

your 3rd and 1st equation says that W is useless in your system. (divide by 2 your first equationto see it)

lets change your 3rd equation by : a+b+2c=W

then you can use linsolve to get it :

linsolve([2*a+2*b+2*c=0 3*a+b+2*c=0 a+b+2*c=w],[a b c])

it gives : [-1/2*w, -1/2*w w]

that's a,b and c in term of w.

Thank you primer. Appreciate the help

Im getting error: bad argument value

(10-02-2016 08:51 PM)yland Wrote: [ -> ]Im getting error: bad argument value

Try:

linsolve([2*a+2*b+2*c=0,3*a+b+2*c=0,a+b+2*c=w],[a,b,c])

Mark Hardman

(10-02-2016 05:26 PM)yland Wrote: [ -> ]My friends less expensive ti solves a 3x4 system of linear equations in terms of 4th unknown. How do i do this on my prime?

Example

2a+2b+2c=0

3a+b+2c=0

a+b+c=W

I want to get all my variables in terms of W. The type of problem im solving is a statics problem and im asked to find the maximum weight of flowerpot if the chain can hold a max 50lb tension. So W represents the maximum weight (flowerpot) that the system can hold. How do i input this?

There is something about your system that does not sound right to me: 2*a+2*b+2*c=0 --> (a+b+c)=0 then W=0.

Could you please rewrite the exact equations ?

Best,

Aries ;-)

thanks for the replies and help, those are not actual eqns I just wanted to give an idea of the form I was dealing with. I figured out why I was getting the error, I was not aware of the different ways to access linsolve command. Basicly I was using LinSolve. Now all is well thanks again.

(10-03-2016 05:11 PM)yland Wrote: [ -> ]thanks for the replies and help, those are not actual eqns I just wanted to give an idea of the form I was dealing with. I figured out why I was getting the error, I was not aware of the different ways to access linsolve command. Basicly I was using LinSolve. Now all is well thanks again.

You're welcome, yland ;-)

Best,

Aries :-)