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Mathematics
Mathematics
Problem
If the vector
r
=
a
i
+
2
j
−
3
k
\mathbf{r}=a\mathbf{i}+2\mathbf{j}-3\mathbf{k}
r
=
a
i
+
2
j
−
3
k
has magnitude
7
7
7
, the positive value of
a
a
a
is a)
45
\sqrt{45}
45
b)
6
6
6
c)
7
7
7
d)
2
2
2
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