畫出圖來之後
量出所有線段的長度
對他們做加減乘除
然後試著找出一樣的值
因為很多題目的弦和弦心距都有關
所以我有順帶劃上去..
湊巧就發現了
+ / -檢視主題
由 ☆ ~ 幻 星 ~ ☆ 於 星期日 七月 23, 2006 11:50 pm
[問題]我有問題
由 tangpakchiu 於 星期日 七月 23, 2006 9:00 pm
#ed_op#DIV#ed_cl#想問問幻星這題是怎樣想出來的???#ed_op#/DIV#ed_cl#
由 ☆ ~ 幻 星 ~ ☆ 於 星期日 七月 23, 2006 2:41 pm
延長AO交圓於K
AK=直徑
連BK
過O做OT垂直AB於T
所以AT=BT
因為AT=BT，AO=OK，所以OT=1/2BK
因為AK平行CB，所以AC弧=BK弧
由等弧對等弦
所以AC=BK=2OT=根號(AO^2-1/4*AB^2)=根號(R^2-1/4*a^2)
AK=直徑
連BK
過O做OT垂直AB於T
所以AT=BT
因為AT=BT，AO=OK，所以OT=1/2BK
因為AK平行CB，所以AC弧=BK弧
由等弧對等弦
所以AC=BK=2OT=根號(AO^2-1/4*AB^2)=根號(R^2-1/4*a^2)
[問題]幾何題4
由 tangpakchiu 於 星期日 七月 23, 2006 11:03 am
#ed_op#DIV#ed_cl##ed_op#IMG alt="image file name: 2k84fda2ab87.gif" src="http://yll.loxa.edu.tw/phpBB2/richedit/upload/2k84fda2ab87.gif" border=0#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto"#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#☉#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#O#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#的半徑為#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#R#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#，弦#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#AB=a#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#，弦#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#BC平行#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#OA#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#，求#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-bidi-font-family: 新細明體"#ed_cl#AC#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-font-kerning: 0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體"#ed_cl#的長。請列部驟~~~~~~~#ed_op#/SPAN#ed_cl##ed_op#/P#ed_cl##ed_op#/DIV#ed_cl#