On page 22 of the R-introduction guide it's written:
the quadratic form x^{'} A^{-1} x which is used in
multivariate computations, should be computed by
something like x%*%solve(A,x), rather than computing
the inverse of A.
Why isn't it good to compute t(x) %*% solve(A) %*% x?
Thanks a lot for help!