Hello everyone,

English isn't my native language, so I hope I can make myself clear. I'm new on this forum, because I have a question. I put this topic in this subforum, but I am not sure if this is the right one. Sorry if I'm wrong.

Given is some vector and with following conditions:

with

In this case: . and are constants.

with and with are constants too.

Let be a vector with above mentioned conditions ánd:

Define . Express in , and .

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I have a very difficult time doing this. This is how far I got:

.

So for :

.

I think I have to substitute somewhere in in a way that only , and remain as constants/variables.

Later I found that:

And for :

.

But I don't know what I can do with that.

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Anyone who can help me with this?

Thanks in advance.