please tel me answer of under root 3+4i without calculatot with steps

Question

please tel me answer of under root 3+4i
without calculatot with steps

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Verity 3 years 2021-07-26T00:28:24+00:00 2 Answers 10 views 0

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  1. thuhuong
    0
    2021-07-26T00:29:27+00:00
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    Hello,

    Let's\ say \\\\z=\sqrt{3+4*i} =a+b*i\\\\z^2=3+4*i=(a+b*i)^2=a^2-b^2+2i*a*b\\\\\\if \ a\neq 0\\\left\{\begin{array}{ccc}a^2+b^2&=&3\\2ab=4\\\end{array}\right.\\\\\\\left\{\begin{array}{ccc}b=\dfrac{2}{a}\\a^2-(\dfrac{2}{a})^2=2\\\end{array}\right.\\\\\\a^4-4=3*a^2\\a^4-3a^2-4=0\\\\\Delta=(-3)^2-4*1*(-4)=25=5^2\\\\a^2=4\ or \ a^2=-1 (impossible)\\\\So:\\(a=2\ and\ b=1)\ or\ (a=-2\ and\ b=-1)\\

    Roots are thus 2+i and -2-i

    There is an other using a geometrical formula (formule de Moivre)

  2. giabao
    0
    2021-07-26T00:30:00+00:00
    Reply

    Answer:

    _____ is used to find a certain information from the list?Cell address used in formula is also called as _____?

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )