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YING YONG KE JI
2014年
5期
62-66
,共5页
曲焱炎%栾英艳%何蕊%李平川
麯焱炎%欒英豔%何蕊%李平川
곡염염%란영염%하예%리평천
几何作图%等分圆周%七等分%弦长%近似正七边形
幾何作圖%等分圓週%七等分%絃長%近似正七邊形
궤하작도%등분원주%칠등분%현장%근사정칠변형
geometric construction%circumference in equal parts%seven-divided circumference%chord length%ap-proximate regular-heptagon
在工程施工和现场操作中总会遇到圆周七等分的问题。高等教育课程在几何作图这一节给出了圆周七等分的画法。但课本仅给出了作图方法,而对原理未作解答。在此利用对称原理、勾股定理、余弦定理和切割线定理,推算出教材中近似圆周七等分各弦长的解,并比较了各段弦的近似值与真实值的误差,对圆周七等分作图法进行了证明计算。
在工程施工和現場操作中總會遇到圓週七等分的問題。高等教育課程在幾何作圖這一節給齣瞭圓週七等分的畫法。但課本僅給齣瞭作圖方法,而對原理未作解答。在此利用對稱原理、勾股定理、餘絃定理和切割線定理,推算齣教材中近似圓週七等分各絃長的解,併比較瞭各段絃的近似值與真實值的誤差,對圓週七等分作圖法進行瞭證明計算。
재공정시공화현장조작중총회우도원주칠등분적문제。고등교육과정재궤하작도저일절급출료원주칠등분적화법。단과본부급출료작도방법,이대원리미작해답。재차이용대칭원리、구고정리、여현정리화절할선정리,추산출교재중근사원주칠등분각현장적해,병비교료각단현적근사치여진실치적오차,대원주칠등분작도법진행료증명계산。
The problem of dividing a circle into seven equal parts is very common in engineering construction and on-site operations.A practical construction method of dividing seven equal parts of a circle is presented in descrip-tive geometry section of higher education courses, but the principle of the method has not been proved.In this pa-per, by applying symmetry principle, the pythagorean theorem, cosine theorem and the tangent-secant theory, the solutions of the approximate seven equal division chord length are deduced, and the errors between real values and approximate values of each chord are calculated to illustrate comparisons for researchers.