Polar Equation

Algebra Level 3

$y^2=1-2x$

$\text{if we make this a polar equation what could be the equation?}$

r(1-cos A)=1

1-rcos A=0

r(1+cos A)=1

r-cos A=1

1 solution

Mohammad Khaza
Dec 28, 2017

$y^2=1-2x$

or, $x^2+y^2=1-2x+x^2$

or, $r^2=(1-x)^2$ ..............................[ $x^2+y^2=r^2$ ]

or, $r=1-x$

or, $r+rcos A=1$ .................................[ $x=rcos A$ ]

or, $r(1+cos A)=1$

Why couldn't $r$ be $x-1$ ? We can have $r^2 = (1-x)^2~\Rightarrow~r^2 = (x-1)^2~\Rightarrow~r = x-1$ .

Micah Wood - 2 years ago

@Micah Wood This is also possible, but it is not one of the options given. The question only asks for one possible equation.

Victor Chan - 4 months ago