MCQ
$a=i+j+k,\,b=2i-4k,\,c=i+\lambda \,j+3k$ are coplanar, then the value of $\lambda $ is
- A$5/2$
- B$3/5$
- C$7/3$
- ✓None of these
$\therefore [a b c]$ $ \Rightarrow \,\,\,\left| {\,\begin{array}{*{20}{c}}1&1&1\\2&0&{ - 4}\\1&\lambda &3\end{array}\,} \right|\, = 0$
$ \Rightarrow 4\lambda - \left( {6 + 4} \right) + 2\lambda = 0$
==> $6\lambda = 10\,\,\, \Rightarrow \lambda = \frac{5}{3}$.
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$A = \{ \left( {a,b} \right) \in R \times R:\left| {a - 5} \right| < 1 \,\,and\,\,\left| {b - 5} \right| < 1\} $; $B = \left\{ {\left( {a,b} \right) \in R \times R:4{{\left( {a - 6} \right)}^2} + 9{{\left( {b - 5} \right)}^2} \le 36} \right\}$ then : . . . . .