User:Jonjoseph

[asy] pair O = (0,0); pair P = (2,0); draw(unitcircle); dot(O); dot(P); label('$P$', P, E); label('$C$', O, W); [/asy]

Given a circle with center $C$ and a point $P$ that lies outside the circle, bisect circle $C$ with a second circle centered at $P$.

[asy] pair O = (0,0); pair P = (2,0); pair A = (0,1); pair B = (0, -1); draw(unitcircle); draw(A--B, red); draw(P--O, red); draw(circle(P, 2.24)); dot(O); dot(P); dot(A); dot(B); label('$P$', P, E); label('$C$', O, W);  [/asy]

Problem from class:

[asy] import olympiad; import cse5; import geometry; size(150); defaultpen(fontsize(10pt)); defaultpen(0.8); dotfactor=4;  pair X = origin; pair Y = (3,0); pair W = X+dir(120); pair Z = Y+dir(120); pair T = (0,2); pair S = T+dir(120); pair U = (3,2); pair V = U+dir(120);  label("$X$",X,SW); label("$W$",W,SW); label("$T$",T,NE); label("$S$",S,NW); label("$Z$",Z,E); label("$Y$",Y,SE); label("$U$",U,E); label("$V$",V,NE);  draw(X--Y); draw(Z--Y, dashed); draw(W--X, red); draw(X--Z, red); draw(Z--U, red); draw(Z--W,red); draw(U--X, red); draw(S--T--U--V--cycle); draw(X--T); draw(W--S); draw(Y--U); draw(Z--V,dashed); draw(W--U,red); [/asy]

[asy] unitsize(1 cm); pair A, B, C; A = (0, 0); B = (2, 0); C = (2, 1.5);  draw(A--B--C--cycle); label("$A$", A, W); label("$B$", B, E); label("$C$", C, N); label("$5$", (A+B)/2, S); label("$6$", (B+C)/2, E); label("$\theta$", A, NE); [/asy]

[asy] unitsize(0.2 cm); pair A, B, E, P; A = (0,0); B = (8,0); E=(1,2); P = (B + reflect(A,(1,2))*(B))/2; draw((-10,0)--(10,0)); draw(A+(-1,-2)--8*E, red); draw(A--(0,25)); draw(B+-1*(1,2)--(9, 2)+7*(1,2), red); draw(B--P,dashed); dot("$A$", A, SE); dot("$B$", B, SE); dot("$P$",  P, N); label("$8$", (A + B)/2, S); [/asy]

[asy] size(125); real ticklen=3; real tickspace=2;  real ticklength=0.1cm; real axisarrowsize=0.14cm; pen axispen=black+1.3bp; real vectorarrowsize=0.2cm; real tickdown=-0.5; real tickdownlength=-0.15inch; real tickdownbase=0.3; real wholetickdown=tickdown; void rr_cartesian_axes(real xleft, real xright, real ybottom, real ytop, real xstep=1, real ystep=1, bool useticks=false, bool complexplane=false, bool usegrid=true) {     import graph;     real i;     if(complexplane) {         label("$\textnormal{Re}$",(xright,0),SE);         label("$\textnormal{Im}$",(0,ytop),NW);     } else {         label("$x$",(xright+0.4,-0.5));         label("$y$",(-0.5,ytop+0.2));        }      ylimits(ybottom,ytop);     xlimits( xleft, xright);     real[] TicksArrx,TicksArry;      for(i=xleft+xstep; i<xright; i+=xstep) {         if(abs(i) >0.1) {             TicksArrx.push(i);         }     }     for(i=ybottom+ystep; i<ytop; i+=ystep) {         if(abs(i) >0.1) {             TicksArry.push(i);         }     }      if(usegrid) {         xaxis(BottomTop(extend=false), Ticks("%", TicksArrx ,pTick=gray(0.72),extend=true),p=invisible);//,above=true);         yaxis(LeftRight(extend=false),Ticks("%", TicksArry ,pTick=gray(0.72),extend=true), p=invisible);//,Arrows);     }     if(useticks) {         xequals(0, ymin=ybottom, ymax=ytop, p=axispen, Ticks("%",TicksArry ,  pTick=black+0.8bp,Size=ticklength), above=true,  Arrows(size=axisarrowsize));         yequals(0, xmin=xleft, xmax=xright, p=axispen, Ticks("%",TicksArrx ,  pTick=black+0.8bp,Size=ticklength), above=true,  Arrows(size=axisarrowsize));      } else {         xequals(0, ymin=ybottom, ymax=ytop, p=axispen,  above=true,  Arrows(size=axisarrowsize));         yequals(0, xmin=xleft, xmax=xright, p=axispen,  above=true,  Arrows(size=axisarrowsize));     } }; rr_cartesian_axes(-5,5,-1,10); real f(real x) {return x*x;} real g(real x) {return 2*x*x;} draw(graph(f,-sqrt(10),sqrt(10),operator ..), red ,Arrows(size=axisarrowsize)); draw(graph(g,-sqrt(5),sqrt(5),operator ..), blue ,Arrows(size=axisarrowsize));  //dot((2,4), p=orange); //dot((2,8),p=orange); //draw((2,4)--(sqrt(2),4),p=orange, Arrow(size=2*axisarrowsize)); draw((3,9)--(3/sqrt(2),9),p=black, Arrow(size=2*axisarrowsize)); dot((3, 9), p=black);  //dot((-1,1), p=purple); //dot((-1,2),p=purple); //draw((-1,1)--(-1,2),p=purple, Arrow(size=2*axisarrowsize)); [/asy]

[asy] size(170); draw(circle((0,0),1)); draw((0,0)--(1,0)--(1,.75)--cycle); draw((0.9,0)--(0.9,0.1)--(1,0.1)); label("$\theta$", (0.15,0), NE); label("1", (0.5,0), S); label("$\tan \theta$", (1,.375), E); label("$\sec\theta$", (.5, .375), NW); [/asy]

[asy] size(200);  import three;  currentprojection = orthographic(3.1, 2.1, 1);  triple A, B, X, Y, Z;  A = (1, 1, 0); B = (0, 0, 1);  O = (0,0,0);  X = (1, 0, 0);  Y = (0, 1, 0);  Z = (0, 0, 1);  real big = 2;  draw(surface(-(big - 0.1)*X - (big - 0.1)*Y -- -(big - 0.1)*X + (big - 0.1)*Y -- (big - 0.1)*X + (big - 0.1)*Y -- (big - 0.1)*X - (big - 0.1)*Y--cycle), rgb(226, 253, 255), nolight);  draw(O--big*X, Arrow3(size = 0.2cm));  draw(O-- -big*X, Arrow3(size = 0.2cm)); draw(O-- big*Y, Arrow3(size = 0.2cm));  draw(O-- -big*Y, Arrow3(size = 0.2cm));  draw(O-- big*Z, Arrow3(size = 0.2cm)); draw(O-- -big*Z, Arrow3(size = 0.2cm));  label("$x$", big*X, NW);  label("$y$", big*Y, N);  label("$z$", big*Z, W);  draw(A--B, red, Arrow3(size = 0.3cm));  dot("$A$", A, S);  dot("$B$", B, E);  [/asy]

[asy] import graph;  //size(6cm); picture pic1; real xsize=200, ysize=140; size(pic1,xsize,ysize,IgnoreAspect);  real f(real x){return ((x - .5)^3 - .5 x + 1);} xlimits(pic1,  -2, 2); ylimits(pic1, -2,2); draw(pic1, graph(f,-1,2),black+1bp); xaxis(pic1, Label("$x$",position=EndPoint, align=SE),Ticks("%"), Arrow); yaxis(pic1, Label("$y$",position=EndPoint, align=NW),Ticks("%"), Arrow); labelx(pic1, 1,2S); labely(pic1, 1,2W); label(pic1, "\scriptsize $y = g(x)$", (2.2,1));  picture pic2; size(pic2,xsize,ysize,IgnoreAspect);  real g(real x){return (3(x - .5)^2 - .5);} xlimits(pic2,  -2, 2); ylimits(pic2, -2,2); draw(pic2, graph(g,-0.5,1.5),black+1bp); xaxis(pic2, Label("$x$",position=EndPoint, align=SE),Ticks("%"), Arrow); yaxis(pic2, Label("$y$",position=EndPoint, align=NW),Ticks("%"), Arrow); labelx(pic2, 1,2S); labely(pic2, 1,2W); label(pic2, "\scriptsize $y = g'(x)$", (2.2,1));  picture pic3; size(pic3,xsize,ysize,IgnoreAspect);  real h(real x){return (6(x - .5));} xlimits(pic3,  -2, 2); ylimits(pic3, -2,2); draw(pic3, graph(h,0.1,0.75),black+1bp); xaxis(pic3, Label("$x$",position=EndPoint, align=SE),Ticks("%"), Arrow); yaxis(pic3, Label("$y$",position=EndPoint, align=NW),Ticks("%"), Arrow); labelx(pic3, 1,2S); labely(pic3, 1,2W); label(pic3, "\scriptsize $y = g''(x)$", (2.2,1));  // Fit pic to W of origin: // add(pic.fit(),(0,0),W);  real margin = 5mm; add(pic1.fit(),(0,0), margin * N);  // Fit pic2 to E of (5mm,0): add(pic2.fit(),(0,0), margin * S);  add(pic3.fit(), (0, 0), 12*margin*S); [/asy]