Direction cosines or direction ratios?
Read exercise and reference answers
- Items
- Item
- Written l, m, n
- Category
- Direction cosines
- Item
- Satisfy l² + m² + n² = 1
- Category
- Direction cosines
- Item
- Are actual cosines of angles
- Category
- Direction cosines
- Item
- Written a, b, c
- Category
- Direction ratios
- Item
- Any proportional triple will do
- Category
- Direction ratios
- Item
- Need dividing by √(a²+b²+c²) to normalise
- Category
- Direction ratios
- Categories
- Item
- Direction cosines
- Item
- Direction ratios
Cosines are fixed and normalised
ratios are any proportional triple. Source: syllabus Maths Part II, Ch 11 Three Dimensional Geometry.