

NCERT Solutions for Class 12 Maths Chapter 10 Miscellaneous Exercise
and
with magnitude √3 and 2 respectively having
.
= √6
Solution :
It is given that,
Hence, the angle between the given vectors
and
is π/4.
Question
2. Find the angle between the vectors
.
Solution :
The given vectors are
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.1
Question 3. Find the projection of the vector
on the vector
Solution :
Let
=
and
=
Now, projection of vector
on
is given by,
Hence, the projection of vector
on
is 0.
Question
4. Find the projection of the vector
on the vector
Solution :
Let
=
and
=
Now, projection of vector
on
is given by,
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.2
Question 5. Show that each of the given three vectors is a unit vector:
Also show that they are mutually perpendicular to each other.
Solution :
Hence, the given three vectors are mutually perpendicular to each other.
Question
6. Find
Solution :
Question
7. Evaluate the product
Solution :
Question
8. Find the magnitude of two vectors
and
having the same magnitude such that the angle between them is 60° and their scalar product is 1/2.
Solution :
Let
θ
be the angle between the vectors
and
Question
9. Find
if for a unit vector
.
Solution :
Question
10. If
are such that
+ λ
is perpendicular to
then find the value of λ
Solution :
Given:
Question
11. Show that
is perpendicular to
for any two non-zero vectors
and
Solution :
Question
12. If and
.
= 0 and
.
= 0 , then what can be concluded about the vector
?
Solution :
It is given that
.
= 0 and
.
= 0 .
Hence, vector
satisfying
.
= 0can be any vector.
Question
13. If
,
and
are unit vectors such that
+
+
= 0 find the value of
Solution :
Since,
+
+
= 0
are unit vectors.
Question
14. If either vector
. But the converse need not be true. Justify your answer with an example.
Solution :
Hence, the converse of the given statement need not be true.
Question
15.
If the vertices A, B, C of a triangle ABC are (1, 2, 3), (–1, 0, 0), (0, 1, 2), respectively, then find ∠ABC. [∠ABC is the angle between the vectors
]
Solution :
The vertices of ΔABC are given as A (1, 2, 3), B (–1, 0, 0), and C (0, 1, 2).
Also, it is given that ∠ABC is the angle between the vectors
.
Question
16.
Show that the points A (1, 2, 7), B (2, 6, 3) and C (3, 10, –1) are collinear.
Solution :
The given points are A (1, 2, 7), B (2, 6, 3), and C (3, 10, –1).
Hence, the given points A, B, and C are collinear.
Question
17. Show that the vectors
form the vertices of a right angled triangle.
Solution :
Let vectors
be position vectors of points A, B, and C respectively.
Hence, ΔABC is a right-angled triangle.
Question
18.
If
is a nonzero vector of magnitude ‘
a
’ and λ a nonzero scalar, then
λ
is unit vector if
(A) λ = 1
(
B) λ = –1
(C) a = |
λ
|
(D) a = 1/|
λ|
Solution :
Therefore, option (D) is correct.
