Hi !

If two vectors are parallel, there exists a real number x, different to 0, such that :

So seeing that and , can you set up a relation between -2 and m ?

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Now, if two vectors are perpendicular, this means that the dot product is 0.

For two vectors : and , their dot product is :

So here, what is the dot product of u and v ? Deduce the value of m ?