The distance between the object and the real image formed by a convex lens is d. If the linear magnification is m, find the focal length of the lens in terms of d and m.

Explanation

To find the focal length of a convex lens in terms of the distance \( d \) between the object and the real image, and the linear magnification \( m \), we can follow these steps:

### Step-by-step Solution:

1. **Understanding the Setup**:
- Let \( U \) be the object distance (from the optical center to the object).
- Let \( V \) be the image distance (from the optical center to the image).
- The total distance between the object and the image is given as \( d \), which can be expressed as:
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