Class 12 Three Dimensional Geometry · Short Answer2 Marksorthogonal_directions
Class 12 Maths · Three Dimensional Geometry · Short Answer #75
Find k for which r=(−3,1,5)+t(k−5,1,2k+1) and r=(−2,2,0)+s(−1,k,5) have orthogonal directions.
✅ Step-by-Step Solution
Final Answer: k=−1.
- Set the dot product of the directions equal to zero.
- −(k−5)+k+5(2k+1)=10k+10=0.
- Thus k=−1.
📋 CBSE Stepwise Marking Scheme
- [0.5 marks] Set the dot product of the directions equal to zero.
- [1 mark] −(k−5)+k+5(2k+1)=10k+10=0.
- [0.5 marks] Thus k=−1.
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