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Math Help - Linear program problem solving Dual and using SIMPLEX

  1. #1
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    Linear program problem solving Dual and using SIMPLEX

    i think i had to do tis wrong its taking me a ffreakin life time to solve, can any1 tell me how many interations they did for this problem.... and what kind of numbers there getting, i set

    Find the dual of the following LP and then solve the dual using the simplex

    max -x1 -2x2
    s.t -3x1+x2<= -1
    x1 -x2 <=1
    -2x1+7x2<=6
    9x1-4x2<=6
    -5x1+2x2<=-3
    7x1-3x2<=6
    x1,x2>=0


    here is the dual i got i dunno if u guys will ge tthe same
    where w is the variable i introduced

    min -w1+w2+6w3+6w4-3w5+6w6
    s.t
    -3w1+w2-2w9w4-5w5+7w6<=-1
    w1-w2+7w3-4w4+2w5-3w6<=-2
    w1,w2>=0

    my slack variables are s and t

    so applying simplex i get

    max w1 - w2 - 6w3 - 6w6 +3w5 -6w6

    subject to (s.t.)
    -3w1+w2-2w9w4-5w5+7w6 + s = -1
    w1-w2+7w3-4w4+2w5-3w6 + t = -2
    w1,w2>=0

    now therest is also taking me forever so i think im doion sumthin wrong
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  2. #2
    Senior Member
    Joined
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    Quote Originally Posted by ruprotein View Post
    i think i had to do tis wrong its taking me a ffreakin life time to solve, can any1 tell me how many interations they did for this problem.... and what kind of numbers there getting, i set

    Find the dual of the following LP and then solve the dual using the simplex

    max -x1 -2x2
    s.t -3x1+x2<= -1
    x1 -x2 <=1
    -2x1+7x2<=6
    9x1-4x2<=6
    -5x1+2x2<=-3
    7x1-3x2<=6
    x1,x2>=0


    here is the dual i got i dunno if u guys will ge tthe same
    where w is the variable i introduced

    min -w1+w2+6w3+6w4-3w5+6w6
    s.t
    -3w1+w2-2w9w4-5w5+7w6<=-1
    w1-w2+7w3-4w4+2w5-3w6<=-2
    w1,w2>=0

    my slack variables are s and t

    so applying simplex i get

    max w1 - w2 - 6w3 - 6w6 +3w5 -6w6

    subject to (s.t.)
    -3w1+w2-2w9w4-5w5+7w6 + s = -1
    w1-w2+7w3-4w4+2w5-3w6 + t = -2
    w1,w2>=0

    now therest is also taking me forever so i think im doion sumthin wrong
    Looks correct except that the inequalities are in the wrong direction for the dual so the slack variables have the wrong sign. The Simplex Java Applet will walk you through a solution.
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