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Given $A =\hat{ i }+\hat{ j }+\hat{ k }$ and $B =-\hat{ i }-\hat{ j }-\hat{ k }$, then $( A - B )$ will make angle with $A$
The resultant of $A$ and $B$ makes an angle $\alpha$ with $A$ and $\beta$ with $B$, then
A boat is sent across a river with a velocity of $8\, km/hr$. If the resultant velocity of boat is $10 \,km/hr$, then velocity of the river is ........$km/hr$