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Mathematics
Mathematics
Problem
Angle between diagonals of a parallelogram whose sides are represented by
a
=
2
i
^
+
j
^
+
k
^
a = 2\hat{i} + \hat{j} + \hat{k}
a
=
2
i
^
+
j
^
+
k
^
and
b
=
i
^
−
j
^
−
k
^
b = \hat{i} - \hat{j} - \hat{k}
b
=
i
^
−
j
^
−
k
^
a.
cos
−
1
(
1
3
)
\cos^{-1}\left(\frac{1}{3}\right)
cos
−
1
(
3
1
)
b.
cos
−
1
(
1
2
)
\cos^{-1}\left(\frac{1}{2}\right)
cos
−
1
(
2
1
)
c.
cos
−
1
(
4
9
)
\cos^{-1}\left(\frac{4}{9}\right)
cos
−
1
(
9
4
)
d.
cos
−
1
(
5
9
)
\cos^{-1}\left(\frac{5}{9}\right)
cos
−
1
(
9
5
)
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