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Question
Mathematics
If the foot of perpendicular drawn from the point (2,5 , 1) on a line passing through (α , 2 α , 5) is ((1/5) , (2/5) , (3/5)) , then α is equal to
Q. If the foot of perpendicular drawn from the point
(
2
,
5
,
1
)
on a line passing through
(
α
,
2
α
,
5
)
is
(
5
1
,
5
2
,
5
3
)
, then
α
is equal to
2026
236
NTA Abhyas
NTA Abhyas 2020
Report Error
A
9
19
B
570
11
C
54
57
D
25
1
Solution:
From diagram
PQ
→
⋅
QR
→
=
0
[
(
2
−
5
1
)
i
^
+
(
5
−
5
2
)
j
^
+
(
1
−
5
3
)
k
^
]
⋅
[
(
α
−
5
1
)
i
^
+
(
2
α
−
5
2
)
j
^
+
(
5
−
5
3
)
k
^
]
=
0
⇒
5
9
α
−
25
9
+
5
46
α
−
25
46
+
25
44
=
0
⇒
α
=
25
1