Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Two vectors
A
⃗
\vec{A}
A
and
B
⃗
\vec{B}
B
have equal magnitudes. The magnitude of
(
A
⃗
+
B
⃗
)
(\vec{A} + \vec{B})
(
A
+
B
)
is 'n' times the magnitude of
(
A
⃗
−
B
⃗
)
(\vec{A} - \vec{B})
(
A
−
B
)
. The angle between
A
⃗
\vec{A}
A
and
B
⃗
\vec{B}
B
is: a.
cos
−
1
[
n
2
−
1
n
2
+
1
]
\cos^{-1}\left[\frac{n^2 - 1}{n^2 + 1}\right]
cos
−
1
[
n
2
+
1
n
2
−
1
]
b.
cos
−
1
[
n
−
1
n
+
1
]
\cos^{-1}\left[\frac{n - 1}{n + 1}\right]
cos
−
1
[
n
+
1
n
−
1
]
c.
sin
−
1
[
n
2
−
1
n
2
+
1
]
\sin^{-1}\left[\frac{n^2 - 1}{n^2 + 1}\right]
sin
−
1
[
n
2
+
1
n
2
−
1
]
d.
sin
−
1
[
n
−
1
n
+
1
]
\sin^{-1}\left[\frac{n - 1}{n + 1}\right]
sin
−
1
[
n
+
1
n
−
1
]
Browse the problem library