| 摘要 |
PROBLEM TO BE SOLVED: To enable a learner to visually and geometrically understand the process that the solution of a standard type quadratic equation (x2-ax+b=0) is determined. SOLUTION: This solution determination device consists of a base 7, a wire- shaped material 1, a first measuring member 2 having graduations, a second measuring member 3 having the same graduations as the graduations of the first radius measuring member 2, a slidable slide scale 4 having the graduations and a sliding member 5 formed freely slidably in the longitudinal direction of the slide scale 4. The device is provided with a start point implement 8 in the position where the graduations of the first measuring member 2 are made zero. The implement is provided with a circular part 1a of a suitable diameter. The diameter of the circular part 1a is set equal to the absolute value of the coefft. of the linear term of the standard quadratic equation. In addition, the reading of the solution of the quadratic equation from the slide scale 4 is made possible when the slide scale 4 is slide by the distance equal to the positive square root of the absolute value of the constant term of the standard type quadratic equation from the start point implement 8.
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