Complete the definition of direction cosines

Exercise and reference answers

Missing parts

1. Answer

   cosines

   Choices

   1. cosines
   2. sines
   3. tangents

2. Answer

   coordinate axes

   Choices

   1. coordinate axes
   2. coordinate planes
   3. position vectors

3. Answer

   l² + m² + n² = 1

   Choices

   1. l² + m² + n² = 1
   2. l + m + n = 1
   3. lmn = 1

Complete the statement

Direction cosines of a line are the {0} of the angles the line makes with the positive directions of the {1}. They always satisfy {2}.

Explanation