Question

Which of the following points lies on the graph of r = 2 - 3cosθ?

Answer 1

$\bf (\stackrel{r}{0},\stackrel{\theta }{0^o})\qquad \quad 0=2-3cos(0^o)\implies 0=2-3(1)\implies 0\ne -1 \\\\\\ (\stackrel{r}{1},\stackrel{\theta }{0^o})\qquad \quad 1=2-3cos(0^o)\implies 1=2-3(1)\implies 1\ne -1 \\\\\\ (\stackrel{r}{2},\stackrel{\theta }{0^o})\qquad \quad 2=2-3cos(0^o)\implies 2=2-3(1)\implies 2\ne -1 \\\\\\ (\stackrel{r}{-1},\stackrel{\theta }{0^o})\quad \quad -1=2-3cos(0^o)\implies -1=2-3(1)\implies -1=-1$