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Question
Mathematics
The number of values of k for which the linear equations 4 x+k y+2 z=0 k x+4 y+z=0 2 x+2 y+z=0 possess a non-zero solution is
Q. The number of values of
k
for which the linear equations
4
x
+
k
y
+
2
z
=
0
k
x
+
4
y
+
z
=
0
2
x
+
2
y
+
z
=
0
possess a non-zero solution is
1868
228
AIEEE
AIEEE 2011
Report Error
A
Zero
B
3
C
2
D
1
Solution:
For non-trivial solution of given system of linear equations
∣
∣
4
k
2
k
4
2
2
1
1
∣
∣
=
0
⇒
8
+
k
(
2
−
k
)
+
2
(
2
k
−
8
)
=
0
⇒
−
k
2
+
6
k
−
8
=
0
⇒
k
2
−
6
k
+
8
=
0
⇒
k
=
2
,
4
Clearlv there exists two values of
k