Let q be the quadratic form on R3 given by
q(x1,x2,x3)=x1x2+2x1x3+x32.
Find an invertible linear operator U on R3 such that
(U†q)(x1,x2,x3)=x12−x22+x32.
(Hint: Express U as a product of operators similar to those used in Exercises 5 and 6.)