Homework 10.3, pp. 686--, #4, 8, 28

#4

r1=-Sqrt[2];
t1=5Pi/4;
r2=1;
t2=5Pi/2;
r3=2;
t3=-7Pi/6;
x1=r1*Cos[t1];
y1=r1*Sin[t1];
x2=r2*Cos[t2];
y2=r2*Sin[t2];
x3=r3*Cos[t3];
y3=r3*Sin[t3];
{{x1,y1},{x2,y2},{x3,y3}}
ListPlot[{{x1,y1},{x2,y2},{x3,y3}},PlotMarkers->{Automatic,Large}]

#8: this is the sector of a circle of radius 2 (not including the boundary).

p1=Graphics[{Orange,Disk[{0,0},2,{Pi,3 Pi/2}]}];
p2=Graphics[{Dashed,Circle[{0,0},2,{Pi,3 Pi/2}]}];
Show[p1,p2]

#28a:

(x-2)^2+(y-3)^2=5^2
r=4