Statement 1: If the points $(1,2,2),(2,1,2)$ and $(2,2, z)$ and $(1,1,1)$ are coplanar, then $z=2$.…

Statement 1: If the points $(1,2,2),(2,1,2)$ and $(2,2, z)$ and $(1,1,1)$ are coplanar, then $z=2$. Statement 2: If the 4 points $P, Q, R$ and $S$ are coplanar, then the volume of the tetrahedron $P Q R S$ is 0.
  1. Statement 1 is false,, Statement 2 is true.
  2. Statement 1 is true, Statement 2 is false.
  3. Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation of Statement 1.
  4. Statement 1 is true, Statement 2 is true, Statement 2 is not a correct explanation of Statement 1.

Solution

Statement-1 Points (1, 2, 2), (2, 1, 2), (2, 2, z) and (1, 1, 1) are coplanar then $z=2$ which is false. $ \begin{aligned} & \because\left|\begin{array}{ccc} 1 & -1 & 0 \\ 1 & 0 & z-2 \\ 0 & -1 & -1 \end{array}\right|=0 \\ & \Rightarrow 1(z-2)+1(-1)=0 \Rightarrow z=3 \end{aligned} $ Statement $-2$ is the true statement

Asked in: JEE Main 2012 (12 May Online)

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