Answer: cos(theta) = 1/2.
- A cos(theta) = 0
- B cos(theta) = 1
- C cos(theta) = 1/2
- D cos(theta) = 1/sqrt(2)
Correct answer: C. cos(theta) = 1/2
Explanation: cos(theta) = (a<sub>1</sub>a<sub>2</sub>+b<sub>1</sub>b<sub>2</sub>+c<sub>1</sub>c<sub>2</sub>)/(|d1||d2|) = (0+1+0)/(sqrt(2)*sqrt(2)) = 1/2. theta = 60 degrees.
Three mutually perpendicular axes x, y, z meeting at the origin O, with a point P located by its (x, y, z) coordinates.
Concept context
Lines and planes in 3D space, direction cosines, distances, and angles