標題:
數學 Factors And Measurement
發問:
Please show all clear steps.1) Which of the following expressions have a factor of x+2?I. x^2-4II. 2x^2-x-10III. 5x+10Multiple Choice2) Which of the following expressions represents the volume of the cylinder?(height: 3x-1, diameter: 2x+4)A. V= 派(6x^2+10x-4)B. V= 派(3x^3-x^2+12x-4)C. V=... 顯示更多 Please show all clear steps. 1) Which of the following expressions have a factor of x+2? I. x^2-4 II. 2x^2-x-10 III. 5x+10 Multiple Choice 2) Which of the following expressions represents the volume of the cylinder?(height: 3x-1, diameter: 2x+4) A. V= 派(6x^2+10x-4) B. V= 派(3x^3-x^2+12x-4) C. V= 派(3x^3+11x^2+8x-4) D. V= 派(12x^3+32x-16) 3) Calculate the volume of the cone.(slant height: 25cm, top of the cone: 40degree) A. 210cm^3 B. 1799cm^3 C. 1914cm^3 D. 2168cm^3 Please show all clear steps for all the questions, thank you :)
1) III. 5x+10 5x+10=5(x+2) 2) C. V= 派(3x^3+11x^2+8x-4) Volume of the cylinder = π(radius)^2(height) = π((2x+4)/2)^2(3x-1) = π(x+2)^2(3x-1) = π(x^2+4x+4)(3x-1) = π(3x3+11x2+8x-4) 3) B. 1799cm^3 Radius of the base = 25sin20° Height of the cone = 25cos20° Volume of cone = (1/3)π(radius)^2(height) = (1/3)π(25sin20°)^2(25cos20°) = 1798.6cm3 2013-05-27 07:48:00 補充： On Question 3, radius of the base, height and slant height of the cone form a right triangle. Therefore the angle between height and slant height = 40°/2 = 20° Base radius and height are obtained by trigonometric ratios sinθ= opposite/hypotenuse and cosθ = adjacent / hypotenuse
其他解答:
Thanks for correcting the first answer^^|||||(1) All I, II, III contains the factor (x+2) I. x^2 - 4 = x^2 - 2^2 <-- a^2 - b^2 = (a+b)(a-b) = (x+2)(x-2) II. 2x^2 - x - 10 =(2x-5)(x+2) <-- ax^2 + bx + c = (px +q)(rx + s) III. 5x + 10 = 5(x+2) Therefore all I, II, III contain the factor (x+2) The other two question, the answer given by the first anwserer is correct. 我就唔再重覆打以免浪費網絡資原了。
數學 Factors And Measurement
發問:
Please show all clear steps.1) Which of the following expressions have a factor of x+2?I. x^2-4II. 2x^2-x-10III. 5x+10Multiple Choice2) Which of the following expressions represents the volume of the cylinder?(height: 3x-1, diameter: 2x+4)A. V= 派(6x^2+10x-4)B. V= 派(3x^3-x^2+12x-4)C. V=... 顯示更多 Please show all clear steps. 1) Which of the following expressions have a factor of x+2? I. x^2-4 II. 2x^2-x-10 III. 5x+10 Multiple Choice 2) Which of the following expressions represents the volume of the cylinder?(height: 3x-1, diameter: 2x+4) A. V= 派(6x^2+10x-4) B. V= 派(3x^3-x^2+12x-4) C. V= 派(3x^3+11x^2+8x-4) D. V= 派(12x^3+32x-16) 3) Calculate the volume of the cone.(slant height: 25cm, top of the cone: 40degree) A. 210cm^3 B. 1799cm^3 C. 1914cm^3 D. 2168cm^3 Please show all clear steps for all the questions, thank you :)
此文章來自奇摩知識+如有不便請留言告知
最佳解答:1) III. 5x+10 5x+10=5(x+2) 2) C. V= 派(3x^3+11x^2+8x-4) Volume of the cylinder = π(radius)^2(height) = π((2x+4)/2)^2(3x-1) = π(x+2)^2(3x-1) = π(x^2+4x+4)(3x-1) = π(3x3+11x2+8x-4) 3) B. 1799cm^3 Radius of the base = 25sin20° Height of the cone = 25cos20° Volume of cone = (1/3)π(radius)^2(height) = (1/3)π(25sin20°)^2(25cos20°) = 1798.6cm3 2013-05-27 07:48:00 補充： On Question 3, radius of the base, height and slant height of the cone form a right triangle. Therefore the angle between height and slant height = 40°/2 = 20° Base radius and height are obtained by trigonometric ratios sinθ= opposite/hypotenuse and cosθ = adjacent / hypotenuse
其他解答:
Thanks for correcting the first answer^^|||||(1) All I, II, III contains the factor (x+2) I. x^2 - 4 = x^2 - 2^2 <-- a^2 - b^2 = (a+b)(a-b) = (x+2)(x-2) II. 2x^2 - x - 10 =(2x-5)(x+2) <-- ax^2 + bx + c = (px +q)(rx + s) III. 5x + 10 = 5(x+2) Therefore all I, II, III contain the factor (x+2) The other two question, the answer given by the first anwserer is correct. 我就唔再重覆打以免浪費網絡資原了。
文章標籤
全站熱搜
留言列表
