How do you graph $2=r cos(θ + 180°)$ ?

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Answer 1 · 2016-02-15T10:02:57

it is a vertical Line $x=-2$

From the given

$2=r*cos (theta+180)$

$2=r*[cos theta cos 180-sin theta sin 180]$

$2=r*[cos theta(-1)-sin theta (0)]$

$2=r*(-cos theta-0)$

$2=-r*cos theta$

recall $r=sqrt(x^2+y^2)$ and $cos theta=x/sqrt(x^2+y^2)$

and the equation becomes

$2=-sqrt(x^2+y^2)*x/sqrt(x^2+y^2)$

$2=-cancelsqrt(x^2+y^2)*x/cancelsqrt(x^2+y^2)$

$2=-x$
and

$x=-2" " "$ a vertical line which is the equivalent of

$2=r*cos (theta+180)$

graph{y=1000000x+21000000[-10,10,-5,5]}

have a nice day ...from the Philippines!

How do you graph 2=r cos(θ + 180°)2=r cos(θ + 180°)?