The normalising relation

Exercise and reference answers

Questions

1. Question

   l² + m² + n² equals

   Choices

   1. 0
   2. 1
   3. 3

   Correct choice

   1

2. Question

   A direction cosine can be

   Choices

   1. greater than 1
   2. imaginary
   3. negative

   Correct choice

   negative

3. Question

   To turn ratios a, b, c into cosines, divide by

   Choices

   1. √(a² + b² + c²)
   2. a + b + c
   3. abc

   Correct choice

   √(a² + b² + c²)

Explanation