MHT CET202020 Oct 2020Evening ShiftMathematicsThree Dimensional GeometryActual
A line makes an angle of 45^ with x -axis and congruent angles with y and z -axes, then the direction cosines of the line are
Options
- A1 2 , 1 2 , 1 2 and - 1 2 ,- 1 2 ,- 1 2
- B1 2 , 1 2 , 1 2 and - 1 2 ,- 1 2 ,- 1 2
- C1 2 , 1 2 , 1 2 and - 1 2 ,- 1 2 ,- 1 2
- D1 2 , 1 2 , 1 2 and 1 2 ,- 1 2 ,- 1 2
Correct answer
D. 1 2 , 1 2 , 1 2 and 1 2 ,- 1 2 ,- 1 2
Step-by-step solution
Let angle made by line with each of X and Z axis be . ² 45^ + ² + ² =12 ² =1- 1 2 = 1 2 ² = 1 4 = 1 2 Hence d.r.s. are 1 2 , 1 2 , 1 2 or 1 2 , -1 2 , -1 2