1. Jun 19, 2004

### jcsd

How can you define a four vector in mathcad?

Bascially, I want to adjust the vector (mutiplying by arbitary constants if necessary):

$$I = \left(\begin{array}{c}cdt\\dx\\dy\\dz\end{array}\right)$$

such that:

$$|I|^2 = c^2dt^2 - dx^2 - dy^2 - dz^2$$

2. Jun 19, 2004

### chroot

Staff Emeritus
You need the (Minkowski) metric to take the inner product.

- Warren

3. Jun 19, 2004

### jcsd

I worked out eventually that all I needed to do was mutiply were suitable by i and take the inner product of I and I.