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Thread: Another help!

  1. #1

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    Another help!

    Hello again, I faced a new problem with math, I'm not smart in English math because I don't study Math in English, hope you understand this situation!

    This time with Simultaneous mixed equations:
    ax+by=m

    cx2+dy2=n

    The codes are:

    Dim a, b, c, d, m, n As Integer
    Dim x1, y1, x2, y2 As Double

    a = Val(Txt_a.Text)
    b = Val(Txt_b.Text)
    m = Val(Txt_m.Text)
    c = Val(Txt_c.Text)
    d = Val(Txt_d.Text)
    n = Val(Txt_n.Text)
    x1 = (m * a * d + Math.Sqrt(m ^ 2 * a ^ 2 * d ^ 2 - (b ^ 2 * c + a ^ 2 * d) * (d * m ^ 2 - b ^ 2 * n))) / (b ^ 2 * c + a ^ 2 * d)

    x2 = (m * a * d - Math.Sqrt(m ^ 2 * a ^ 2 * d ^ 2 - (b ^ 2 * c + a ^ 2 * d) * (d * m ^ 2 - b ^ 2 * n))) / (b ^ 2 * c + a ^ 2 * d)

    y1 = (m - a * x1)
    y2 = (m - a * x2)
    Txt_x1.Text = Convert.ToString(x1)
    Txt_x2.Text = Convert.ToString(x2)
    Txt_y1.Text = Convert.ToString(y1)
    Txt_y2.Text = Convert.ToString(y2)

    I'm sure that the bug is from equations' solution.

  2. #2

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    Re: Another help!

    Here is a picture:
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  3. #3
    Hyperactive Member 2kaud's Avatar
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    Re: Another help!

    x1, x2 seem right. But for y1, y2

    y1 = (m - a * x1) / b

    y2 = (m - a * x2) / b
    All advice is offered in good faith only. You are ultimately responsible for the effects of your programs and the integrity of the machines they run on. Anything I post, code snippets, advice, etc is licensed as Public Domain https://creativecommons.org/publicdomain/zero/1.0/

    C++17 Compiler: Microsoft VS2017 (15.5.0)

  4. #4

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    Re: Another help!

    It was like this but didn't work correctly.

  5. #5
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    Re: Another help!

    What are the equations you are trying to solve? What should be the answers? I solved the ones given in post #1 algebraically and got the same values for x1, x2 as used in the code. y1, y2 should be as post #3.
    All advice is offered in good faith only. You are ultimately responsible for the effects of your programs and the integrity of the machines they run on. Anything I post, code snippets, advice, etc is licensed as Public Domain https://creativecommons.org/publicdomain/zero/1.0/

    C++17 Compiler: Microsoft VS2017 (15.5.0)

  6. #6

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    Re: Another help!

    The Equations:
    -1x+2y=2
    3x^2 +4y^2=28

    The expected answers:
    X= 2 Y= 2

    The given answers:
    X1= 2 X2= 2
    Y1= -3 Y2= -0.5
    Last edited by casper.mta; Dec 6th, 2017 at 01:16 PM.

  7. #7

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    Re: Another help!

    hm? still waiting you

  8. #8
    Hyperactive Member 2kaud's Avatar
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    Re: Another help!

    The given answers:
    X1= 2 X2= 2
    Y1= -3 Y2= -0.5
    Somehow you're mixed up the names. The correct solution is
    Code:
    x1 = 2 y1 = 2
    x2 = -3 y2 = -0.5
    As a quadratic is involved, there must be two answers (which can be the same or complex).
    All advice is offered in good faith only. You are ultimately responsible for the effects of your programs and the integrity of the machines they run on. Anything I post, code snippets, advice, etc is licensed as Public Domain https://creativecommons.org/publicdomain/zero/1.0/

    C++17 Compiler: Microsoft VS2017 (15.5.0)

  9. #9

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    Re: Another help!

    Thank you again!

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