推 doom8199:a/b 、 1+1/[1+(a/b)] 07/04 12:43
→ GUOpp:第三題可以參考lim sinθ/θ=0 as θ->0的證明(微積分) 07/05 00:12
1.Let a and b be positive integers.Prove that √2
always lies between the two fractions a/b and (a+2b)/(a+b)
2.Let f:S->T be a function. IF Y≦T
,we denote by -1
f (Y) the largest subset of S which f maps into Y
That is -1
f (Y)={x:x＜S and f(x)＜Y} (找不到屬於符號 用＜表示)
Prove that
-1 -1 -1
f (Y1∩Y2)=f (Y1)∩f (Y2)
3. for |x|≦1 ,show that
|cosx|≦|sinx/x|≦1
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※ 編輯: u2150260 來自: 122.116.6.196 (07/04 10:49)