The focal length of a mirror is given by (1)/(f) = (1)/(u) +...

Options

1. A$\dfrac{∆ f}{f} = \dfrac{∆ u}{u} + \dfrac{∆ v}{v}$
2. B$\dfrac{∆ f}{f} = \dfrac{∆ u}{u} + \dfrac{∆ v}{v} - \dfrac{∆ \left(u + v\right)}{u + v}$
3. C$\dfrac{∆ f}{f} = \dfrac{∆ u}{u} + \dfrac{∆ v}{v} - \dfrac{∆ \left(u - v\right)}{u + v}$
4. D$\dfrac{∆ f}{f} = \dfrac{∆ u}{u} + \dfrac{∆ v}{v} + \dfrac{∆ u}{u + v} + \dfrac{∆ v}{u + v}$