# Math Help - Quick Question about Vector Notation

1. ## Quick Question about Vector Notation

I'm currently in the 4th week or so of my "Calculus 3/Multivariable Calculus" class and I learned about 2 ways to multiply vectors, the cross product and the dot product.

I often see this kind of notation though in my book (assume a, b, and c are vectors and not scalars) where it'll be something like (a x b)c. How do I multiply the cross product of vector a x b to c when I don't know which kind of multiplication to use?

Thanks for your time and help.

2. Originally Posted by PeterTheBohemian
I'm currently in the 4th week or so of my "Calculus 3/Multivariable Calculus" class and I learned about 2 ways to multiply vectors, the cross product and the dot product.

I often see this kind of notation though in my book (assume a, b, and c are vectors and not scalars) where it'll be something like (a x b)c. How do I multiply the cross product of vector a x b to c when I don't know which kind of multiplication to use?

Thanks for your time and help.
I think they're referring to $\left(a\times b\right)\cdot c$. Otherwise, that wouldn't really make sense since you can't use regular multiplication when "multiplying" vectors.

Also, note that $\left(a\cdot b\right)c$ is valid since $a\cdot b$ is a scalar.

Does this help? If not, please post back.

3. Thanks Chris. I just needed someone else to think "That doesn't make sense." I must have just misread my professor's writing or something, because I understand the concept of how you can't cross multiply a vector and a scalar.