If l, m, n are the direction cosines of the line x-1=2(y+3)=1-z, then what is l^4+m^4+n^4 equal to?

NDA 2021 Mathematics question

If , , are the direction cosines of the line , then what is equal to?

Answer: (B)

Write the line in symmetric form: . The direction ratios are , i.e. . Their magnitude is , so the direction cosines are

Create a free account to read the complete working, and practise questions like this in a timed test.

Question ID VK-033558