I used a series of elementary transformation to reduce a matrix to a tridiagonal matrix. when I wrote the program in notebook, I run step by step. everything ran well and it give me explicitly the result of a matrix.
but after I save this notebook and open it after a day, I run the whole notebook and print out the product of these elementary transformation, Mathematica does not give me explicit result of matrix, it gives me a product of these elementary transformation. do not know why. I print out Print[V] and here is my result: