Image Formation by a Convex Mirror
- A convex mirror always forms a virtual, erect, and diminished image behind the mirror.
- The image is always located between the pole and focus of the mirror. 
Derivation of the Mirror Equation
Using the sign convention:
- The mirror formula is given by: \[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \] where:
- \( f \) = Focal length of the mirror
- \( u \) = Object distance
- \( v \) = Image distance
For a convex mirror, \( f \) and \( v \) are positive, while \( u \) is negative. Thus, the mirror equation holds for both concave and convex mirrors.

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?