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I have a final exam after tomorrow, ,so I hope if anybody can help

1) How to find a unit vector that is orthogonal to both u=(1,1,0) and v=(-1,0,1) ?

2) How to determine whether the given planes are parallel :

3x_2y+z =6 and 2x_y+4z=0

I know how to determine whether the planes are perpendicular, it's to product their normals and get a zero. Is not?

3) when should I use the cross product?

Thanx you alot,

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# Homework Help: 3 questions about the vectors

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