Answer
See below.
Work Step by Step
a) Plugging in $(0.5,0.5)$ into the formula: $0.5^2+0.5^2=0.25+0.25=0.5\ne$, thus it is not on the graph.
b) Plugging in $(0.5,\frac{\sqrt3}{2})$ into the formula: $0.5^2+(\frac{\sqrt3}{2})^2=0.25+0.75=1$, thus it is on the graph.
