close
標題:
04年數學會考題目 急急急
發問:
尼個網址入面有4條會考題,好難解到,請好心人幫幫忙!thx~ http://hk.pg.photos.yahoo.com/ph/wing13com2002/album?.dir=5957scd&.src=ph&store=&prodid=&.done=http%3a//hk.pg.photos.yahoo.com/ph/wing13com2002/my_photos 除此之外,另一題:一個橙子及一個蘋果的價錢分別為$2及$3。現在花費了$46購買若干個橙子和蘋果。若所購買的橙子和蘋果的總數為20,求所購買橙子的數目。(答案14個) 註:所有題目要列全式,thanks!
最佳解答:
9. (a) 設r cm為扇形的半徑 πr^2 (80°/360°) = 162π r^2 = 729 r = 27 ∴ 扇形的半徑是27cm (b) 扇形的周界 = 2πr (80°/360°) + 2r = π(27) (1/9) + 2(27) = (3π + 54)cm 10. (a) 設y = ax^2 + bx, a和b為非零常數 當x = 3, y = 3 9a + 3b = 3 3a + b = 1......(i) 當x = 4, y = 12 16a + 4b = 12 4a + b = 3......(ii) (ii) - (i) : a = 2 Sub. a = 2 into (i) 3(2) + b = 1 b = -5 ∴ y = 2x^2 - 5x (b) ∵ y < 42 ∴2x^2 - 5x < 42 2x^2 - 5x - 42 < 0 (2x + 7)(x - 6) < 0 ∴ -7/2 < x < 6 因x是整數, x 所有可取值為 -3, -2, -1, 0, 1, 2, 3, 4及5 12. (a)(i) ∵ CD = CE ∴ ∠CED = ∠CDE = 36° 所以∠AEF = ∠CED = 36° (ii) ∠ACB = ∠CDE + ∠CED = 36°+ 36°= 72° ∵ AB = AC ∴ ∠ABC = ∠ACB = 72° ∵ ∠BAC = 180°- 72°- 72° ∴ ∠BAC = 36° (b)(i)在ΔAEF ∠BFE = 36°+ 36°= 72°(Δ的外角) ∵ ∠AEF = ∠EAF = 36° ∴ AF = EF(底角相等) ∵ AF = FB ∴ EF = FB ∠FEB + ∠FBE + 72° = 180°(Δ的內角和) ∠FEB = ∠FBE = (180°- 72°)/2 = 54°(等腰Δ底角) ∠AEB = 54°+ 36°= 90° ∴∠AEB 是一個直角 (ii) cos36°= 10/AB AB = 10/cos36° ΔABC的面積 = 1/2 (AB)(AC)sin36° = 1/2 (10/cos36°)^2 sin36° = 44.9cm^2 13. (a)(i) 設E的座標為(x, y) x = (2 + 8)/2 = 5 y = (9 + 1)/2 = 5 ∴E的座標是(5, 5) (ii) ∵ ABCD是一個菱形 ∴ BD垂直於AC AC的斜率 = (9 - 1)/(2 - 8) = -4/3 BD的斜率 = -1/(-4/3) = 3/4 BD的方程是 y - 5 = 3/4 (x - 5) 3x - 4y + 5 = 0......(1) (b)(i)BC的斜率 = AD的斜率 = -1/7 BC的方程是 y - 1 = -1/7 (x - 8) x + 7y - 15 = 0......(2) (ii) 設B的座標為(h, k) 代 (h, k) 入 (1) 和 (2) 3h - 4k + 5 = 0......(3) h + 7k - 15 = 0......(4) (3) - 3x(4) : -25k + 50 = 0 k = 2 代 k = 2 入 (4) : h + 7(2) - 15 = 0 h = 1 ∴ B的座標是(1, 2) AB = √[(2 - 1)^2 + (9 - 2)^2] = √50 = 5√2 你另外的題目 設分別買了橙子和蘋果a個和b個 a + b = 20......(i) 2a + 3b = 46......(ii) 3 x (i) - (ii): (3a + 3b) - (2a + 3b) = 60 - 46 a = 14 ∴ 購買橙子的數目是14個 呼~~終於完成了 2007-01-12 15:55:10 補充： 計錯了(b) 扇形的周界= 2πr (80°/360°) 2r= π(27) (4/9) 2(27)= (12π 54)cm
Let the number of orange bought be x, then the number of apple bought wil be (20 - x) By given, we have 2x + 3(20 - x) = 46 Simplify gives x = 14|||||let 橙 be x 蘋果 be y 2x+3y=46---------a x+y=20-------b a-3b x=14 ,y=6 橙有14個|||||設買了橙x個，蘋果y個 因為共花了$46，所以3x+2y=46...(1號式) 因為總數為20，所以x+y=20 則係y=20-x...(2號式) 將2號式代入1號式 3x+2(20-x)=46 3x+40-2x=46 x=6 y=14
04年數學會考題目 急急急
發問:
尼個網址入面有4條會考題,好難解到,請好心人幫幫忙!thx~ http://hk.pg.photos.yahoo.com/ph/wing13com2002/album?.dir=5957scd&.src=ph&store=&prodid=&.done=http%3a//hk.pg.photos.yahoo.com/ph/wing13com2002/my_photos 除此之外,另一題:一個橙子及一個蘋果的價錢分別為$2及$3。現在花費了$46購買若干個橙子和蘋果。若所購買的橙子和蘋果的總數為20,求所購買橙子的數目。(答案14個) 註:所有題目要列全式,thanks!
最佳解答:
9. (a) 設r cm為扇形的半徑 πr^2 (80°/360°) = 162π r^2 = 729 r = 27 ∴ 扇形的半徑是27cm (b) 扇形的周界 = 2πr (80°/360°) + 2r = π(27) (1/9) + 2(27) = (3π + 54)cm 10. (a) 設y = ax^2 + bx, a和b為非零常數 當x = 3, y = 3 9a + 3b = 3 3a + b = 1......(i) 當x = 4, y = 12 16a + 4b = 12 4a + b = 3......(ii) (ii) - (i) : a = 2 Sub. a = 2 into (i) 3(2) + b = 1 b = -5 ∴ y = 2x^2 - 5x (b) ∵ y < 42 ∴2x^2 - 5x < 42 2x^2 - 5x - 42 < 0 (2x + 7)(x - 6) < 0 ∴ -7/2 < x < 6 因x是整數, x 所有可取值為 -3, -2, -1, 0, 1, 2, 3, 4及5 12. (a)(i) ∵ CD = CE ∴ ∠CED = ∠CDE = 36° 所以∠AEF = ∠CED = 36° (ii) ∠ACB = ∠CDE + ∠CED = 36°+ 36°= 72° ∵ AB = AC ∴ ∠ABC = ∠ACB = 72° ∵ ∠BAC = 180°- 72°- 72° ∴ ∠BAC = 36° (b)(i)在ΔAEF ∠BFE = 36°+ 36°= 72°(Δ的外角) ∵ ∠AEF = ∠EAF = 36° ∴ AF = EF(底角相等) ∵ AF = FB ∴ EF = FB ∠FEB + ∠FBE + 72° = 180°(Δ的內角和) ∠FEB = ∠FBE = (180°- 72°)/2 = 54°(等腰Δ底角) ∠AEB = 54°+ 36°= 90° ∴∠AEB 是一個直角 (ii) cos36°= 10/AB AB = 10/cos36° ΔABC的面積 = 1/2 (AB)(AC)sin36° = 1/2 (10/cos36°)^2 sin36° = 44.9cm^2 13. (a)(i) 設E的座標為(x, y) x = (2 + 8)/2 = 5 y = (9 + 1)/2 = 5 ∴E的座標是(5, 5) (ii) ∵ ABCD是一個菱形 ∴ BD垂直於AC AC的斜率 = (9 - 1)/(2 - 8) = -4/3 BD的斜率 = -1/(-4/3) = 3/4 BD的方程是 y - 5 = 3/4 (x - 5) 3x - 4y + 5 = 0......(1) (b)(i)BC的斜率 = AD的斜率 = -1/7 BC的方程是 y - 1 = -1/7 (x - 8) x + 7y - 15 = 0......(2) (ii) 設B的座標為(h, k) 代 (h, k) 入 (1) 和 (2) 3h - 4k + 5 = 0......(3) h + 7k - 15 = 0......(4) (3) - 3x(4) : -25k + 50 = 0 k = 2 代 k = 2 入 (4) : h + 7(2) - 15 = 0 h = 1 ∴ B的座標是(1, 2) AB = √[(2 - 1)^2 + (9 - 2)^2] = √50 = 5√2 你另外的題目 設分別買了橙子和蘋果a個和b個 a + b = 20......(i) 2a + 3b = 46......(ii) 3 x (i) - (ii): (3a + 3b) - (2a + 3b) = 60 - 46 a = 14 ∴ 購買橙子的數目是14個 呼~~終於完成了 2007-01-12 15:55:10 補充： 計錯了(b) 扇形的周界= 2πr (80°/360°) 2r= π(27) (4/9) 2(27)= (12π 54)cm
此文章來自奇摩知識+如有不便請留言告知
其他解答:Let the number of orange bought be x, then the number of apple bought wil be (20 - x) By given, we have 2x + 3(20 - x) = 46 Simplify gives x = 14|||||let 橙 be x 蘋果 be y 2x+3y=46---------a x+y=20-------b a-3b x=14 ,y=6 橙有14個|||||設買了橙x個，蘋果y個 因為共花了$46，所以3x+2y=46...(1號式) 因為總數為20，所以x+y=20 則係y=20-x...(2號式) 將2號式代入1號式 3x+2(20-x)=46 3x+40-2x=46 x=6 y=14
文章標籤
全站熱搜
留言列表
