one assumption i made is the symbol is a diverging lens
if this assumption is valid, then
maybe u can explore this http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1155.0
and find out yourself.
picture 1 seems possible, u know where? appears to me to be at F on the right [img]http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=2312.0;attach=4492;image[/img]
pictue 2 seems to require the object to be an infinity on the right side
picture 3 i cant get it, is it a trick question?