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Math Help - Solve for a and b if:

  1. #1
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    Solve for a and b if:

    Solve for a and b if: (jb)/(1-j)=(a-j)2j

    Any help will be much appreciated.
    Thanks in advance
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  2. #2
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    Re: Solve for a and b if:

    Quote Originally Posted by Scoplex View Post
    Solve for a and b if: (jb)/(1-j)=(a-j)2j

    Any help will be much appreciated.
    Thanks in advance
     \frac {b\cdot j}{1-j}=2+2a \cdot j \Rightarrow b \cdot j =(2+2a \cdot j)(1-j) \Rightarrow

     \Rightarrow b \cdot j = (2a+2) +(2a-2) \cdot j \Rightarrow

     \Rightarrow 2a-2 = b ~\text {and}~2a+2=0
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  3. #3
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    Re: Solve for a and b if:

    Quote Originally Posted by princeps View Post
     \frac {b\cdot j}{1-j}=2+2a \cdot j
    How did you arrive at 2 + 2aj?
    Isn't it 2aj - 2j^2 ?
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  4. #4
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    Re: Solve for a and b if:

    Quote Originally Posted by Wilmer View Post
    How did you arrive at 2 + 2aj?
    Isn't it 2aj - 2j^2 ?
    j^2=-1
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  5. #5
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    Re: Solve for a and b if:

    Well, you sure got me confused! We start with:
    (j*b) / (1 - j) = 2*j*(a - j)

    We're to solve for a and b;
    b is straightforward: b = [2j(a - j)(1 - j)] / j

    Solving for a leads to:
    a = [2j(j - 1) - b] / [2(j -1)]

    That checks out perfectly with the initial equation.
    And there's loads of solutions; examples with all positive integers:
    (a,b,j) = (1,2,2), (2,4,3), (1,8,3), (3,6,4), (4,8,5)

    Can you explain why you jump to j^2 = -1 ?
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  6. #6
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    Re: Solve for a and b if:

    I think that j is imaginary unit .
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  7. #7
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    Re: Solve for a and b if:

    Quote Originally Posted by princeps View Post
    I think that j is imaginary unit .
    Why? Absolutely no mention of that in original post.
    Anyway, ask me if I care
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