I have a line segment (begin $(x_1,y_1)$, end $(x_2,y_2)$, with $D=5$, let’s say) and a circle (radius $R$, center $(x_3,y_3)$)
How can I check that if my line segment intersects my circle?
picture
http://kepfeltoltes.hu/120129/inter_www.kepfeltoltes.hu_.png