In[]:=
(*replacesrank-2column-matrixvectorwithrank-1vector*)​​MakeExpression[RowBox[{"(",GridBox[{{a_},{b_}}],")"}],form_]:=​​MakeExpression[RowBox[{"{",RowBox[{a,",",b}],"}"}],form];​​​​​​​​crcChord5[{h_,k_},r_,line_]:=​​RegionPlot​​ImplicitRegion[line,{x,y}],​​PlotRange
h-2r
h+2r
,
k-2r
k+2r
,​​Epilog​​Circle
h
k
,r,​​Red,PointSize@Large,Point
x
y
/.#&/@​​Solveline,
x
y
∈Circle
h
k
,r​​;​​​​​​​​MakeExpression[RowBox[{"(",GridBox[{{a_},{b_}}],")"}],form_]=.;(*unset*)
crcChord5[{1,2},3,y-x+1==0]
Out[]=