Linear Algebra matrix form

How do they get the 1/8?I understand that from the equation above a=1/2 but shouldn’t b=1/4 or do you have to multiply by 2 becuase of the matrix from equation (ax^2 + 2bxy +cy^2)

(edited 11 months ago)

Reply 1

ghostwalker

Original post by Stress2638,,,

How do they get the 1/8?I understand that from the equation above a=1/2 but shouldn’t b=1/4 or do you have to multiply by 2 becuase of the matrix from equation (ax^2 + 2bxy +cy^2)

If you multiply out, you'll see that you get an "xy" term from the lower left element of the 2x2 matrix, and from the upper right element, adding the two gives you the coefficient of 1/4 (=2b), hence they're 1/8 each.