The system configuration of web services changes day by day, and many people want to perform version control in the same way as program code. With the free open source software ' drawthe.net ', you ...

Draw a ray from the object to the lens that is parallel to the principal axis. Once through the lens, the ray should pass through the principal focus. Draw a ray which passes from the object through ...

A ray diagram shows how light travels, including what happens when it reaches a surface. In a ray diagram, you draw each ray as: a straight line; with an arrowhead pointing in the direction that the ...