Mathematical wide-angle planting problem: how to plant trees at two ends or at one end or at two ends?

Tree planting is divided into straight-line tree planting and circular tree planting.

Ring planting, interval number = planting ring length ÷ interval length (inter-plant distance)

Linear tree planting

Number of sections = road length/section length

Plant at both ends: number of plants = number of intervals+1.

Planting trees at one end: number of trees = number of intervals.

No planting at both ends: number of plants = number of intervals-1.

If you are satisfied, please accept it. Oh, thank you.