第11單元 一元二次方程式(二)
例題3
設\( ax^2+bx+c=0 \)之二根均為無理數,且此二根之近似值為0.8470703308及-0.5930703308。若\( a,b,c \in Z \),且(a,b,c)=1,又a>0,|b|≦10,|c|≦10,計算a=,b=,c=。【1996ARML試題】
第12單元 數列級數(一) 有限數列與級數
例題4
\( n \in N \),\( a_n=\sqrt{n} \)之最接近之整數值。(1)\( m \in N \),滿足\( a_n=m\)之自然數n之個數=。(用m表示) (2)\( \displaystyle \sum^{2001}_{k=1}a_k \)=。【日本國立橫濱大學】
感謝billyhun提供個人筆記照片檔,網址在附件裡。
h ttps://dl.dropboxusercontent.com/u/23455489/%E5%85%AC%E9%96%8B%E4%B8%8B%E8%BC%89%E7%9A%84%E6%AA%94%E6%A1%88/billyhun%E6%95%99%E7%94%84%E7%AD%86%E8%A8%98.zip 連結已失效
112.7.4補充
若多項式方程式\(x^3+ax^2+bx+c=0\)的三個根為\(\displaystyle cos \frac{2\pi}{7}\)、\(\displaystyle cos \frac{4\pi}{7}\)、\(\displaystyle cos \frac{6\pi}{7}\),其中角度是弳度,則乘積\(abc\)之值為多少?
(112新竹高中代理,https://math.pro/db/thread-3765-1-1.html)
以下是我的補充說明
math pro和美夢成真就有看不完的資料了,那為什麼還要組讀書會,但就我這幾年的觀察其實大多數的人都只是默默下載題目和看現成的解答而已,遇到看不懂或是解題時卡住的,除非身旁有人可以問否則就只能先擱著,看別人的解答不求甚解的吞下去,不僅容易忘掉而且考試時改個條件就解不出來了。而我在回答問題時也會將步驟寫的比較精簡,反正沒人提問就當你已經懂了。
在空間坐標中,\(A(1,-1,2),B(1,1,0),C(1,0,4)\),\(P\)為平面\(E\):\(x+y+z=0上的動點\),則\(\overline{AP}^2+\overline{BP}^2+\overline{CP}^2\)之最小值為。
(108麗山高中,https://math.pro/db/thread-3113-1-1.html)
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求證\(\displaystyle\frac{1}{\sin24^{\circ}}+\frac{1}{\sin48^{\circ}}+\frac{1}{\sin96^{\circ}}=\frac{1}{\sin168^{\circ}}\)。
(115高雄市高中聯招,https://math.pro/db/thread-4121-1-1.html)
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The function \(f\) has the property that, for each real number \(x\), \(f(x)+f(x-1)=x^2\).
If \(f(19)=94\), what is the remainder when \(f(94)\) is divided by 1000?
(1994AIME,https://artofproblemsolving.com/ ... _Problems/Problem_3)
令\(x_1,x_2,\ldots,x_{18}\)為方程式\(x^{18}+4x^{11}+1=0\)的18個根,求\((x_1^4+x_1^2+1)(x_2^4+x_2^2+1)\ldots(x_{18}^4+x_{18}^2+1)\)的值為何?
(112學年度第2學期中山大學雙週一題第3題,連結有解答https://www-math.nsysu.edu.tw/~problem/2024s/2024s3.pdf)
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Find the least positive integer \(n\) for which \(\displaystyle\frac{n-13}{5n+6}\) is a non-zero reducible fraction.
(A)45 (B)68 (C)155 (D)226 (E) none of these
(1985AHSME,連結有解答https://artofproblemsolving.com/ ... Problems/Problem_26)
將半徑為10公分的三個球放入一半球形碗中,發現此三球的頂端恰與此碗頂端位於同一水平面,請問此半球形狀的碗之半徑為多少公分?
(110學年度第2學期中山大學雙週一題第5題)
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Canadian Mathematical Olympiad https://cms.math.ca/competitions/cmo/
1978
Determine the largest real number \(z\) such that \(\matrix{x+y+z=5\cr xy+yz+xz=3}\) and \(x,y\) are also real.
1986
In the diagram line segments \(AB\) and \(CD\) are of length 1 while angles \(ABC\) and \(CBD\) are \(90^{\circ}\) and \(30^{\circ} \)respectively. Find \(AC\).
設\(P\)為\(\Delta ABC\)的\(BC\)邊上一點,且\(\overline{PB}=\overline{AC}=a\),若\(\displaystyle\angle BAP=\frac{1}{3}\angle PAC=30^{\circ}\),則\(\overline{PC}=\)。
(95台中一中,https://math.pro/db/viewthread.php?tid=987&page=2#pid22591)
1994
Evaluate the sum \(\displaystyle \sum_{n=1}^{1994}(-1)^n\frac{n^2+n+1}{n!}\).
Show that every positive integral power of \(\sqrt{2}-1\) is of the form \(\sqrt{m}-\sqrt{m-1}\) for some positive integer \(m\).
(e.g. \((\sqrt{2}-1)^2=3-2\sqrt{2}=\sqrt{9}-\sqrt{8}\)).
(相關問題,https://math.pro/db/viewthread.php?tid=2769&page=1#pid17237)
1996
Find all real solutions to the following system of equations. Carefully justify your answer.
\(\cases{\displaystyle \frac{4x^2}{1+4x^2}=y\cr \frac{4y^2}{1+4y^2}=z\cr \frac{4z^2}{1+4z^2}=x}\)
(相關題目101中正高中,https://math.pro/db/viewthread.php?tid=1422&page=1#pid6438)
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這裡有大量教甄試題解答,需要很多時間整理