- #1
Apple&Orange
- 30
- 2
Homework Statement
x12+x1x2+2x22=8
a) Write the equation using a quadratic form i.e. [itex]\underline{x}[/itex]TA[itex]\underline{X}[/itex]=8
b)Find the Matrix Q such that the transformation [itex]\underline{X}[/itex]=Q[itex]\underline{Y}[/itex] diagonalises A and reduces the quadratic form to standard form in terms of coordinates (y1,y2)
Homework Equations
[itex]\underline{X}[/itex]=Q[itex]\underline{Y}[/itex]
[itex]\underline{X}[/itex]TA[itex]\underline{X}[/itex]=8
The Attempt at a Solution
For question b), I got the A matrix as [1 1;0 2] or [1 0.5;0.5 2] *sorry, don't know how to use the matrix operator so I've written it MATLAB style*.
I used the first matrix to give a better looking eigenvalues, which resulted in 2 and 1. From the values, I got a vector of [1;0] and [1;1]
Using the vectors, I got a Q matrix of [1 0; 1/sqrt(2) 1/sqrt(2)]
and using [itex]\underline{X}[/itex]=Q[itex]\underline{Y}[/itex], I got
2.707y12+2.707y1y2+y22 which I'm not even sure if its right.
Could someone please assist me in tackling this question?
Thanks!