Q204 / 270 · NDA 2012 (Phase 2) · Mathematics

If a line OP of length $r$ (where ' $O$ ' is the origin) makes an angle $\alpha$ with $x$-axis and lies in the $x z$-plane, then what are the coordinates of P ?

  • Correct answer
    A
    $(r \cos \alpha, 0, r \sin \alpha)$
  • B
    $(0,0, r \sin \alpha)$
  • C
    $(r \cos \alpha, 0,0)$
  • D
    $(0,0, r \cos \alpha)$

Solution

The coordinate of P will be $(r \cos \alpha, 0, r \sin \alpha)$ $\because y$ coordinate will be zero.

Hence, the correct answer is option: 'A'.

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