Two are true, one is not

Exercise and reference answers

Questions

1. False statement

   Direction ratios also satisfy a² + b² + c² = 1

   Statements

   1. Direction ratios are proportional to direction cosines
   2. Direction cosines satisfy l² + m² + n² = 1
   3. Direction ratios also satisfy a² + b² + c² = 1

2. False statement

   Skew lines meet at exactly one point

   Statements

   1. Skew lines meet at exactly one point
   2. Skew lines lie in different planes
   3. Skew lines are neither parallel nor intersecting

3. False statement

   r = a + λb is the equation of a plane

   Statements

   1. r = a + λb passes through the point with position vector a
   2. r = a + λb is the equation of a plane
   3. r = a + λ(b − a) passes through both given points

Explanation