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3 and 4 .Determinants and Matrices
hard
$c \in R$ का अधिकतम मान, जिसके लिए रैखिक समीकरण निकाय $x-c y-c z=0$, $c x-y+c z=0$, $c x+c y-z=0$ का एक अतुच्छ हल है, है -
A
$-1$
B
$0.5$
C
$2$
D
$0$
(JEE MAIN-2019)
Solution
For non -trivial solution
$D = 0$
$\left| {\begin{array}{*{20}{c}}
1&{ – c}&{ – c}\\
c&{ – 1}&c\\
c&c&{ – 1}
\end{array}} \right| = 0 \Rightarrow 2{c^3} + 3{c^2} – 1 = 0$
$ \Rightarrow {\left( {c + 1} \right)^2}\left( {2c – 1} \right) = 0$
$\therefore $ Greatest value of $c$ is $\frac{1}{2}$
Standard 12
Mathematics