Hiya

Can anyone shed any light on this?

I'm trying to multiply a point in an elliptic curve group.

The curve is over . As an example, I'll use - this point is indeed in the elliptic group.

I believe the rule for multiplication in this case is that: is given by:

where

So by my working out..

I'm not sure how to get any further with this. The answer here is that therefore .

But I have no idea why

Can anyone help?

Thanks for any suggestions!