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How to find solutions to equations involving imaginary numbers?

I need to find a solution to (a+bi)^2= (1 + j) /(2)^0.5 but im getting no sensible answers when im working through

4 Answers

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  • ?
    Lv 7
    5 years ago
    Favorite Answer

    Mistake: i=j?

    If so, then

    (a+bi)^2=(1+i)/sqrt(2)

    =>

    sqrt(2)(a^2-b^2)=1------(1)

    2sqrt(2)ab=1------------(2)

    Putting (2) in (1) get

    a^2-1/(8a^2)=1/sqrt(2)=>

    8a^4-8a^2/sqrt(2)-1=0=>

    a=+/-0.9502081

    a=+/-0.4424802i

    From (2),

    b=0.35355339/a=>

    b=+/-2.976639674

    b=-/+0.799026464i

    Since a, b are real, the answers

    are

    a=0.9502081, b=2.976639674

    a=-0.9502081, b=-2.976639674

  • 5 years ago

    I solved this problem using difference of perfect squares.

    Therefore, instead of writing (a+bi)^2, I am going to write z^2.

    Also, the complex number '(1 + j) /(2)^0.5' is an eyesore, so I am just going to say write 'z_c' where: z_c = (1 + j) /(2)^0.5

    (a+bi)^2 = (1 + j) /(2)^0.5

    (z)^2 = z_c

    (z)^2 - z_c = 0

    (z)^2 - [(z_c)^(1/2)]^2 = 0

    (z_c)^(1/2) = 1∠(pi/8)

    (z)^2 - [1∠(pi/8)]^2 = 0

    [ z + 1∠(pi/8) ] * [ z - 1∠(pi/8) ] = 0

    [ z + 1∠(pi/8) ] * [ z + 1∠(9*pi/8) ] = 0

    [ z_1 + 1∠(pi/8) ] * [ z_2 + 1∠(9*pi/8) ] = 0

    Therefore, the two solutions are shown below

    z_1 = -1∠(pi/8) = 1∠(9*pi/8)

    z_2 = - 1∠(9*pi/8 = 1∠(pi/8)

  • None
    Lv 7
    5 years ago

    What are you solving for? Remember that both i and j are used to denote √-1

  • Como
    Lv 7
    5 years ago

    Let us use j rather than i

    Presentation is open to doubt so having to take a guess at :-

    [ a + j b ]

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