I have equation from the form a*b=c. where a is a row vector of [1*4] b is a column vector of [4*1] and c is a number. I want to get equation of the forum b=…

How can I do it?

Thanks

Ditza

- Feb 7th 2007, 05:25 AMditzafarVector transferring from the left side of the equation to the right
I have equation from the form a*b=c. where a is a row vector of [1*4] b is a column vector of [4*1] and c is a number. I want to get equation of the forum b=…

How can I do it?

Thanks

Ditza - Feb 7th 2007, 07:56 AMThePerfectHacker
- Feb 7th 2007, 08:07 AMCaptainBlack
- Feb 11th 2007, 06:48 AMRebesques
Well... I think it can be done if we look at it as matrix multiplications. If the entries of a are nonzero, then the (4*1) vector d with entries the reciprocals of the entries of a, satisfies a*d=4, so if we multiply the equation a*b=c by d and treat everything as matrices (and since the associative law holds in this case), we get d*a*b=c*d or b=(c/4)*d. This is only a specific solution; The dot product - as Captainblack noted - guarantees there are infinitely many.

Edit: In fact, four uknowns (the entries of b) minus one equation (ab=c --- this is only because of the dot product) we get three degrees of freedom for the solution. Will stop blabbering now.