(a) Using the ray diagram for a system of two lenses of focal lengths `f_(1) and f_(2)` in contact with each other, show that the two lens system can be regarded as equivalent to a single lens of focal length f, where
`(1)/(f)=(1)/(f_(1))+(1)/(f_(2))`
Also write the relation for the equivalent power of the lens combination.
(b) Determine the position of the image formed by the lens combination given in the figure.