| 摘要 |
PURPOSE:To find an optimum initial value required in finding an inverse number by Newton-Rapson method by using a straight line expression of -AX+B set so as to have at least one intersection with an inverse number curve 1/X for the inverse number curve 1/X corresponding to the numeric value X of a section between 0.5-1.0 possible to be taken by a mantissa part. CONSTITUTION:The inverse number curve 1/X for the section 0.5-1.0 of the numeric value X possible to be taken by the mantissa part is found, and the straight line -CX+D connecting the point P3 of the inverse number 2.0 of a minimum value 0.5 to the point P4 of the inverse number 1.0 of a maximum value 1.0 is used for the curve 1/X. At this time, a gradient, the inverse of C goes to -2 and a constant D goes to 3 from two points P3 and P4. In other words, the straight line -CX+D shown in broken line goes to a simple expression (-2X+3), and it is possible to find the initial value X corresponding to an arbitrary numeric value X of the mantissa part in the above section.
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