Mozda ti ovo moze pomoci:

http://books.google.ba/books?i...&lpg=PA353&dq=(a+x+b)+*+(c+x+d)+%3D+(a+*+c)+*+(b+*+d)+-+(b+*+c)+*+(a+*+d).&source=web&ots=TGGo51B8zD&sig=FgH0A0lS6LsXa8Hjp_mYe5pQ7v8&hl=bs&sa=X&oi=book_result&resnum=1&ct=result

http://mb.sparknotes.com/mb.ep...3&f=1&p=5&t=362107

http://en.wikipedia.org/wiki/Lagrange%27s_identity

evo nest sta sam nasla..

CxD=S
(AxB)*S = A*BxS
BxS= BxCxD = (B*D)C-(B*C)D ..... [1]
A*{(B*D)C - (B*C)D}
(A*C)(B*D)-(B*C)(A*D) = (A*C)(B*D)-(A*D)(B*C)

Moze se koristitibilo koji od identiteta , . Takodje, treba ti identitet .

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