*Isaac Newton determined the binomial series as... (1+x) =1+kx+ k ( k - 1) x k ( k - 1) ( k - 2) x k ( k - 1) ( k - 2) ( k - 3)x + + +... 2! 3! 4! Use this to determine a cubic approximation for f ( x ) =- V ( 1 + x )