GraphingCalculator 4;
Window 60 84 824 1224;
PaneDivider 374;
SignificantDigits 14;
FontSizes 14;
StackPanes 1;
R 0 10;
2D.GraphPaper 0;
Text "Circles

Version 1.0 12-11-16

C is the center of the circle.  Q is (optionally) a point on its circumference.  

Either set the radius R by hand (slider), or drag Q to resize.";
Color 2;
Expr C=3.71875+3.46875*i;
Color 7;
Expr Q=5.5625+4.328125*i;
Color 3;
Expr X_1=Re([C]),Y_1=Im([C]);
Color 5;
Expr X_2=Re([Q]),Y_2=Im([Q]);
Color 4;
Expr S=abs(C-Q);
Color 8;
Expr S;
Text "Drag Q to resize:";
Expr [x-X_1]^2+[y-Y_1]^2=S^2;
Color 17;
Expr [x-X_1]^2+[y-Y_1]^2<S^2;
Color 17;
Expr vector(X_1+t*[X_2-X_1],Y_1+t*[Y_2-Y_1]);
Text "Set radius manually:";
Color 6;
MathPaneSlider 44;
Expr R=slider([0,5]);
Color 17;
Expr [x-X_1]^2+[y-Y_1]^2=R^2;
Color 17;
Expr [x-X_1]^2+[y-Y_1]^2<R^2;
Text "In polar coordinates, with radius R and center at polar coordinates (b,2pi*B):";
MathPaneSlider 68;
Expr b=slider([0,10]);
Color 2;
MathPaneSlider 16;
Expr B=slider([0,1]);
Color 17;
Expr R^2=r^2+b^2-(2*b*r*cos([theta-(2*pi*B)]));
Text "Center and radius:";
Color 17;
Expr vector(b*cos([2*pi*B]),b*sin([2*pi*B]));
Color 17;
Expr theta=2*pi*B,r<b;
Color 17;
Expr vector(b*cos([2*pi*B]),b*sin([2*pi*B])+t*R);
Text "From y-axis:";
Color 17;
Expr R^2=r^2+b^2-(2*b*r*sin([theta-(2*pi*B)]));
Text "
Author: David A. Craig <<http://web.lemoyne.edu/~craigda>";