Vector dot product and scalar multiplication in Grapher.app
If you want to multiply two column vectors don't you have to transpose one of them? I got the transpose operator by typing ^T. (That's caret + T, not Ctrl+T)

I was able to multiply a vector by a scalar.



In your screenshot, the subscripts aren't consistent. Maybe it's part of your problem or maybe it's just some math I don't understand. This is all on the edge of my math knowledge.

Epilogue

For those who are interested, here is bjz's screenshot of his working version: