Statement-1: Any vector in space can be uniquely written as the linear combination of three non-coplanar vectors. Statement-2: If $\vec a,\vec b,\vec c$ are three non-coplanar vectors and r is any vector in space, then $[\vec a\,\,\vec b\,\,\vec r]\vec c+[\vec b\,\,\vec c\,\,\vec r]\vec a+[\vec c\,\,\vec a\,\,\vec r]\vec b=[\vec a\,\,\vec b\,\,\vec c]\vec r$ |
Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. Statement-1 is True, Statement-2 is False. Statement-1 is False, Statement-2 is True. |
Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. |
Clearly, statement-1 is true. We have, $\vec r = x\vec a+y\vec b +z\vec c$ ...(i) Taking product successively with $\vec b ×\vec c, \vec c×\vec a$ and $\vec a×\vec b$, we obtain $x=\frac{[\vec b\,\,\vec c\,\,\vec r]}{[\vec a\,\,\vec b\,\,\vec c]},y=\frac{[\vec c\,\,\vec a\,\,\vec r]}{[\vec a\,\,\vec b\,\,\vec c]}$ and $z=\frac{\vec a\,\,\vec b\,\,[\vec r]}{[\vec a\,\,\vec b\,\,\vec c]}$ Substituting the values of x, y, z in (i), we get $[\vec a\,\,\vec b\,\,\vec r]\vec c+[\vec b\,\,\vec c\,\,\vec r]\vec a+[\vec c\,\,\vec a\,\,\vec r]\vec b=[\vec a\,\,\vec b\,\,\vec c]\vec r$ So, statement-2 is true. But, statement-2 is not a correct explanation for statement-1. |