quick C4 vector question

How are you getting 25?

a.b is not |ab|

But a.a =|a|^2

How are you getting 25?

a.b is not |ab|

But a.a =|a|^2

And what would |ab| equal?

And what would |ab| equal?

= |a||b| = 6

That would be |a||b|, unless he's using the notation that if u is a vector then u is the modulus of that vector. But in that case the absolute value signs around ab would be unnecessary as the value of ab would already be positive.

$a=\pm 2$ and $b = \pm 3$

So $ab = \pm 6$

In any case, $|ab| = 6$ always.

a and b are vectors?