A unit vector a makes an angle \[\frac{\pi }{4}\] with z-axis. If \[\mathbf{a}+\mathbf{i}+\mathbf{j}\] is a unit vector, then a is equal to [IIT 1988]

\[\frac{\mathbf{i}}{2}+\frac{\mathbf{j}}{2}+\frac{\mathbf{k}}{\sqrt{2}}\]

\[\frac{\mathbf{i}}{2}+\frac{\mathbf{j}}{2}-\frac{\mathbf{k}}{\sqrt{2}}\]

\[-\frac{\mathbf{i}}{2}-\frac{\mathbf{j}}{2}+\frac{\mathbf{k}}{\sqrt{2}}\]

A unit vector a makes an angle \[\frac{\pi }{4}\] with z-axis. If \[\m

1.	A unit vector a makes an angle \[\frac{\pi }{4}\] with z-axis. If \[\mathbf{a}+\mathbf{i}+\mathbf{j}\] is a unit vector, then a is equal to [IIT 1988]
A.	\[\frac{\mathbf{i}}{2}+\frac{\mathbf{j}}{2}+\frac{\mathbf{k}}{\sqrt{2}}\]
B.	\[\frac{\mathbf{i}}{2}+\frac{\mathbf{j}}{2}-\frac{\mathbf{k}}{\sqrt{2}}\]
C.	\[-\frac{\mathbf{i}}{2}-\frac{\mathbf{j}}{2}+\frac{\mathbf{k}}{\sqrt{2}}\]
D.	None of these
Answer» D. None of these

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A unit vector a makes an angle \[\frac{\pi }{4}\] with z-axis. If \[\mathbf{a}+\mathbf{i}+\mathbf{j}\] is a unit vector, then a is equal to [IIT 1988]

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