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## Homework Statement

Fidn the total multiplications and divisions needed for the LU Decomp. of a general n x n matrix A, whose entries satisfy [itex]a_{ij} = 0[/itex] if [itex]j ≤ i - 2[/itex]

Assume n=5.

Also f ind the total multiplications and divisions needed for solving the lower triangular system Lg=f and for Ux=g.

## The Attempt at a Solution

I drew out the matrix to visualize it, but it's still a bit confusing. First i have to triangularize the bottom left, but there are only 4 digits which need to be zeroed due to the zero structure of the matrix. So for this portion of the LU decomposition, would there be only 5+4+3+2 multiplications needed?