linera solver and cas

01012016, 10:25 PM
Post: #1




linera solver and cas
Hi,
happy new year ! I know there is a linear solver app, but it's limited to number, and I wanted to see how I can play with cas with linear system. system is : 2xa*y=2 x2y=1 I typed linsolve([2*xa*y=2 x2*y=1],[x y]) and cas gave me : [1 0] But expected result was 1/(2+a) and (a+4)/(a+2) Ok... let's try with solve() that is a little bit the swiss knife of cas. first of all, lets try with a basic system : solve(3*x+2*y=1 AND 3*xy=2 , {x,y}) return {[5/9 1/3]} which is correct ! I was very enthousiatic! then I tried : solve(2*xa*y=2 AND x2*y=1, {x,y}) but I got {[1 0]} something look wrong, any idea ? 

01022016, 08:50 AM
Post: #2




RE: linera solver and cas
[1,0] is correct, check your equations!


01022016, 04:21 PM
Post: #3




RE: linera solver and cas
Solving by substitution, we have x=(12*y).
"Plugging" x=(12*y) into the other equation and solving for "y", we have: 2*(12*y)a*y=2 > 24*ya*y=2 > (4a)*y=0 > y=0 (a<>4). Now "plugging" this yvalue back into either equation and solving for "x", we have x=1. Hence the Prime is correct. Best, Aries ;) 

01022016, 09:32 PM
Post: #4




RE: linera solver and cas
yes, you are right, I made mistake while copying equation.
both solve() and linsolve() perfectly works. sorry... 

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