# Homework Help: Finding the inner product formulla

1. Nov 20, 2009

### lom

once i solve that one is the derivative of the other

but here its much harder to guess the formulla
http://i47.tinypic.com/ixt74i.jpg

what is the general method?

Last edited: Nov 21, 2009
2. Nov 20, 2009

### LCKurtz

3. Nov 21, 2009

### lom

i want to find the formula for the inner product which defines such norm.

?

4. Nov 21, 2009

### lom

5. Nov 21, 2009

### HallsofIvy

You still haven't told us what the entire problem is- that looks like part of a problem. Three numbers don't "define" anything!

6. Nov 21, 2009

### lom

i need to find alpha beta and gama
so this expression will be minimal

i know how to solve such stuff
usually
i have a vector and a subspace to make a projection of the vector

so i make an orthogonal basis and then i make a projection of that vector
into my space

and then the difference between that vector and the original vector is the minimal

but in order to do all that i need the
inner product formula which defines this norm.

usually i figured out the formula by guessing

but here i cant guess

so i am asking if there is a general method
?

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