Object at focal point of converging lense

1. Apr 17, 2005

I have a simple question that I can't seem to answer.......

why is it that when an object is at the focal point of a converging lense, the image is at infinity? How can you show this through ray diagrams?

2. Apr 17, 2005

Andrew Mason

The lens equation:

$$\frac{1}{f} = \frac{1}{i} + \frac{1}{o}$$

What is the object distance if i = f? Or, what is the image distance if o = infinity?

AM