Question

If N is the number of unknowns, the number of operations required for backward substitution is ____________

(a) (frac{N^3}{3})

(b) (frac{N^3}{2})

(c) (frac{N^2}{2})

(d) (frac{N^2}{3})

Answer 1

Correct choice is (c) (frac{N^2}{2})

Best explanation: The number of operations required for the overall Gauss elimination method is (frac{N^3}{3}). The number of operations for backward substitution is (frac{N^2}{2}). This high computational cost is the disadvantage of the Gauss elimination method.