20/12/15 09:48:04.93 QEfzM0Mb.net
p=ngon5(col='white',lty=3)
A=p[5]
B=p[1]
line(p[1],p[2],1,3,lty=3,col='white')
line(p[4],p[5],-3,0,lty=3,col='white')
PT <- function(x,A,B) Im(A-B)/Re(A-B)*(x-Re(A))+Im(A)
E=p45=-0.5+1i*PT(-0.5,p[4],p[5])
axy(tan(Arg(p[3]-p[4])),p45,-1,4,lty=3,col='white')
p12=1.8+1i*PT(1.8,p[1],p[2])
C=p12
axy(tan(Arg(p[2]-p[3])),p12,0,2,lty=3,col='white')
seg(p[1],p12,lwd=1)
seg(p[1],p[5],lwd=1)
seg(p[5],p45,lwd=1)
y=tan(Arg(p[3]-p[4]))*(0-Re(p45))+Im(p45)
p450=0+1i*y
y=tan(Arg(p[2]-p[3]))*(0-Re(p12))+Im(p12)
p120=0+1i*y
D=q=intsect(p45,p450,p12,p120)
seg(p45,q,lwd=1)
seg(p12,q,lwd=1)
pt(A,'A')
pt(B,'B')
pt(C,'C')
pt(D,'D')
pt(E,'E')
pt(A/2+E/2,'a')
pt(B/2+C/2,'b')
}
Graph()