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Thread: modulus and argument

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    modulus and argument

    find the modulus and argument of

    (a)6+j
    (b)-5-9j


    do i sub into
    $\displaystyle \sqrt{a^2+b^2}$

    and
    $\displaystyle tan^{-1}\frac{a}{b}$

    many thanks
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  2. #2
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    Quote Originally Posted by decoy808 View Post
    find the modulus and argument of

    (a)6+j
    (b)-5-9j


    do i sub into
    $\displaystyle \sqrt{a^2+b^2}$

    and
    $\displaystyle tan^{-1}\frac{a}{b}$

    many thanks
    For $\displaystyle z = a + jb$ where $\displaystyle j^2 = -1$

    You have your trig ratio wrong, the imaginary axis implies the opposite and the real axis the adjacent

    therefore $\displaystyle \arg (z) =\arctan \left(\frac{b}{a}\right)$

    Otherwise good
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