A) 38
B) 0
C) 10
D) ? 10
Correct Answer: C
Solution :
\[\because \] The vectors \[4\mathbf{i}+11\mathbf{j}+m\mathbf{k},\,7\mathbf{i}+2\mathbf{j}+6\mathbf{k}\] and \[\mathbf{i}+5\mathbf{j}+4\mathbf{k}\] are coplanar. \[\therefore \,\left| \,\begin{matrix} 4 & 11 & m \\ 7 & 2 & 6 \\ 1 & 5 & 4 \\ \end{matrix}\, \right|=0\] \[\Rightarrow 4(8-30)-11(28-6)+m\,(35-2)=0\] \[\Rightarrow -88-11\times 22+33m=0\]\[\Rightarrow -8-22+3m=0\] \[\Rightarrow 3m=30\] \[\Rightarrow m=10.\]You need to login to perform this action.
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