### Shortcut Methods

##### 1 : Lens Formula Shortcut

- When dealing with lenses, if the object is at infinity, you can use a shortcut for the image distance ((v)): $$(v \approx f),$$ where (f) is the focal length of the lens.
- Similarly, if the image is formed at infinity, you can approximate the object distance ((u)) as $$(u \approx -f).$$
- This simplifies calculations for objects far away from or very close to the lens.