image of a parabola y = x^2 under mapping w = -2z + 2i

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Find the image of the parabola y=x2\displaystyle y\,=\,x^2 under the mapping w=2z+2i\displaystyle w\,= \,-2z\,+\,2i

any help? Thanks
 
BlueFalcon said:
Find the image of the parabola y=x2\displaystyle y\,=\,x^2 under the mapping w=2z+2i\displaystyle w\,= \,-2z\,+\,2i

any help? Thanks

Let z=x+iy\displaystyle z=x+iy, then:

w=2(x+iy)+2i\displaystyle w=-2(x+iy)+2i

so:

w=(2x)+i(2y+2)\displaystyle w=(-2x)+i(-2y+2)

So if w=x+iy\displaystyle w=x'+iy', we have:

\(\displaystyle x'=-2x\\
y'=-2y+2=-2x^2+2=-x'^2/2+2\)

Hence the image of y=x2\displaystyle y\,=\,x^2 under the given transformation is y=x2/2+2\displaystyle y=-x^2/2+2

RonL
 
Hello, CaptainBlack!

Welcome aboard!

So you're a "New Member" . . . LOL!
[At your site, I was labelled a "Newbie" for a while.]
 
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