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Mathematics
Mathematics
Problem
A vector has magnitude
5
5
5
units and its direction cosines are
l
=
3
5
,
m
=
4
5
l=\dfrac{3}{5},\; m=\dfrac{4}{5}
l
=
5
3
,
m
=
5
4
. If its
z
z
z
-component is non-negative, the vector is a)
3
i
^
+
4
j
^
+
5
k
^
3\hat{i}+4\hat{j}+5\hat{k}
3
i
^
+
4
j
^
+
5
k
^
b)
3
i
^
+
4
j
^
+
5
k
^
3\hat{i}+4\hat{j}+\sqrt{5}\,\hat{k}
3
i
^
+
4
j
^
+
5
k
^
c)
3
i
^
+
4
j
^
+
0
k
^
3\hat{i}+4\hat{j}+0\hat{k}
3
i
^
+
4
j
^
+
0
k
^
d)
5
i
^
+
4
j
^
+
3
k
^
5\hat{i}+4\hat{j}+3\hat{k}
5
i
^
+
4
j
^
+
3
k
^
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