Polar coordinates

[lament tangle]

can someone explain me why does x^2+y^2=2x is r=2cos(θ)?

I understand that 2x=2cos(θ) but I don't understand why x^2+y^2=r since from what I read r=±sqrt.(x^2+y^2)

[dire wharf]

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[shy nest]

$x^2+y^2=2x\to r^2=2r\cos(\theta)$

[hollow tide]

Omegabet_

[lament tangle]

Oh, ok thanks I wans't calculating 2x right

[shy nest]

yep

[lament tangle]

is it supposed for me to close this channel? or just leave it like this?