→ chuo :1.C 48-48*(1-3/4)*(1*2/3)=44 04/27 23:10
→ chuo :3.D 選到以r/3為半徑裡的小圓即可 04/27 23:11
→ yueayase :2.可用定義作,n(S)=1^2+2^2+...+10^2=10*11*21/6=385 04/28 01:29
→ yueayase :99*1/385+...+(100-n)n/385+...+90*10/385 04/28 01:30
→ yueayase :=sigma(100n-n^2)*1/385=(100*55-385)/385=100/7-1 04/28 01:33
→ yueayase :=93/7 04/28 01:33
推 arnychen :第一題可以當集合算 兩個交集是1/2 聯集就是11/12 04/28 15:54
→ a01059942 :比較想要知道第三題為什麼是要選3/R裡面的圓 04/28 19:44
→ a01059942 : ↑r/3 04/28 19:46