Question

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

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

Answer 1

The correct option is A $(r\cos \alpha ,0,r\sin \alpha )$

As OP lies on XZ plane so y co-ordinate is 0.
QP=$r\cos \alpha$
PR=$r\sin \alpha$
Co-ordinate of P=$(r\cos \alpha ,0,r\sin \alpha )$
Option A is correct