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help solving this equation

2z^2 + 2iz -1 =0

2007-11-13 17:22:19 · 3 answers · asked by Anonymous in Science & Mathematics Mathematics

3 answers

a=2
b=2i
c=-1
now just plug and chug!

-b+/-[√(b^2 -4ac)]/2a
-2i +/- [√(-2i)^2 - 4(2)(-1)]/2(2)
-2i +/- [√-4+8]/4

z= [-i +/- 1]/2
simple and quick!

2007-11-13 19:09:08 · answer #1 · answered by Anonymous · 0 0

I assume that z is the complex variable x + iy;

The equation expands to

2[x^2 + 2ixy - y^2] + 2ix - 2y - 1 = 0

collect the real terms and imaginary terms

2x^2 - 2y^2 - 2y - 1 + (4xy +2x)i = 0

For the whole to be zero, both real and imaginary parts must be zero

first the imaginary part: 4xy + 2x = 0, y = -0.5

put this into the real part

2x^2 - 0.5 - +1 - 1 = 0

2x^2 = 0.5, x = √.25 = ±0.5

The answer is then ±0.5 - 0.5i

2007-11-14 01:41:55 · answer #2 · answered by gp4rts 7 · 0 0

2z^2 + 2iz -1 =0

By the quadratic formula

z= (-2i +/- sqrt((2i)^2 - 4(2)(-1)))/(2*2)
= (-2i +/- sqrt(4i^2 + 8))/4
= (-2i +/- sqrt(-4 + 8))/4
= (-2i +/- sqrt(4))/4
= (-2i +/- 2)/4
= -i/2 +/- 1/2

z = 1/2 - i/2 or -1/2 - i/2

2007-11-14 01:39:37 · answer #3 · answered by PeterT 5 · 0 0

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