Posts by Ray

Total # Posts: 693

  1. Math (Stats)

    Consider the the distribution of under-inflated tires on a four-wheel automobile. The mass density is given by: p(0) = 0.4, p(1) = p(2) = p(3) = 0.1, p(4) = 0.3 a) Find the expected value and the variance of this distribution. b) For what proportion of such cars will the ...
  2. Chemistry

    The dimerization of butadiene is a second order reaction process. In an experiment a sample of 0.0087 mol of butadiene was heated in a liter flask. After 600 seconds 21% of the butadiene has dimerized. Calculate the rate constant.
  3. History

    Also after looking up the author of the site you gave me the person didn't seem to be "look up able" so eh... ;^;
  4. History

    What happened to airplane manufacturing after World War II? 1 Airplane manufacturers began producing goods for the oil industry. 2 Airplane manufacturing rebounded and produced airplanes, parts, and equipment. 3 Airplane manufacturing decreased in Texas as shipbuilding became ...
  5. History

    Anyways my answer is now 2.
  6. History

    OK can you explain why you disagree?
  7. History

    I think it's 3
  8. History

    How were prisoner of war camps different from internment camps? 1 Prisoner of war camps held fewer people than internment camps. 2 Prisoner of war camps held captured soldiers. 3 There was more freedom in prisoner of war camps. 4 Prisoner of war camps were run by Texas officials.
  9. Science

    Egg-laying land animals have evolved to produce eggs with tough shells to ensure that 1 external fertilization can take place. 2 the egg and sperm can fuse 3 parental care is unnecessary*** 4 the developing embryo does no dry out
  10. Chemistry

    I reposted because i messed up you need to just stop spamming :l
  11. Science

    Ah ok thanks
  12. Science

    A man with a genetic disease marries a woman who does not carry the disease. It is not possible for their sons to have the disease. The disease must be X-linked dominat Y-linked dominat X-linked reccesive Y-linked reccesive I'm reposting this because i messed up the first ...
  13. Science

    A man with a genetic disease marries a woman who does not carry the disease. It is not possible for their sons to have the disease. The disease must be--- i forgot to post thequestiong XD OMG
  14. Science

    X-linked dominant Y-linked dominant X-linked recessive Y-linked recessive
  15. Geography

    Oh ok Thanks!
  16. Geography

    how did the decade of prosperity affect the lives of many Mexican-Americans in Texas They became wealthier They became migrant laborers They Moved to other states They Entered New Industries My answer is the 3rd one please check that for me!
  17. History

    Oh so c! Thanks
  18. History

    what lead to the belief that Galveston new government system, created after the Galveston hurricane of 1900 hurt the poor This is for connexus help
  19. History

    what efforts did james hogg make to fix the corporate world in Texas? 1 allowed railroads to choose the path of the rail lines 2 created laws against monopolies 3 made his own insurance company 4 made it easier to start companies
  20. Math

    don't forget to square it if your doing feet square by the way
  21. Math

    2,100 feet 30x70 = 2,100
  22. Math

    Bro thanks I got 10/10
  23. English

    1. Which of the following sentences is punctuated correctly? a. The ladiess’s hates were all purple: they looked so pretty. b. We sat down to eat our meal outside; the night was beautiful. c. The string heavyset fighter won his first fight, and he was featured in the ...
  24. physics

    circus juggler performs an act with balls that he tosses with his right hand and catches with his left had. Each ball is launched at an angle of 75° and reaches a maximum height 88 cm above the launching height. If it takes the juggler 0.2 s to catch a ball with his left ...
  25. Math (Slope and Concavity of vector)

    Any ideas?
  26. Math (Slope and Concavity of vector)

    Forgot the closing parenthesis: (2cos(t) + cos(2t))i + (2sin(t) + sin(2t))j + 0k
  27. Math (Slope and Concavity of vector)

    I am given a vector function <2cos(t) + cos(2t), 2sin(t) + sin(2t), 0> (in other words) : (2cos(t) + cos(2t))i + (2sin(t) + sin(2t)j + 0k Compute the slope dy/dx and concavity d^2x/(dx^2) at t = pi/3. I understand that finding the slope of a vector is possible by using ...
  28. Math (Area formed by 3D coordinates)

    Compute the area of the parallelogram formed by A(-2, 1, 4), B(0, -2, 3) C(-1, 6, 5), and D(1, 3, 4). So for this problem, do I turn the four points into two vectors with AD and BC and then take the cross product and then find the magnitude? Taking the cross product and ...
  29. Discrete Math?

    Was wondering, anyone here know discrete math? Specifically regarding to rules of inferences?
  30. Math (Planes)

  31. Math (Planes)

    P given by the equation x + z = 2
  32. Math (Planes)

    Given the equation x + z = 2. Is P parallel to any of the coordinate planes? Is P perpendicular to any of the coordinate planes?
  33. Math

    If two cars started out at the same spot and traveled in opposite directions for 90 minutes at 60miles per hour -far apart in total miles would they be at the end of the 90 minutes?
  34. Math (Evaluating integrals)

    I am trying to prepare for my finals and I'm approached with this question where I'm not entirely clear what the answer should be: Given the function h(t) graphed below, define A(x) = ?[-0.5,x] h(t) dt . (Graph is in the link) Evaluate A...
  35. Math (Sorta dumb question)

    I'm given the equation S = L(1 - e^(-kt)) I am asked to write S as a function of t when L = 100, S = 25 when t = 2 So would my final answer just have S and t as variables? Or have S, t and L as variables? Ended up with S = 100(1 - e^((ln(3/4)/2)*t) Or is the actual answer ...
  36. Banned for cheating!

    It seems like this test cheating issue is more of a recent problem? I've been on this site for over 2 years but only now I've started noticing that there's multiple bans for asking test answers each day :/
  37. Math (Calc) (Differential Equations)

    Ahh I see now. Thanks for your help!
  38. Math (Calc) (Differential Equations)

    The rate of change in the number of miles s of road cleared per hour by a snowplow is inversely proportional to the depth h of snow. That is, ds/dh = k/h Find s as a function of h given that s = 25 miles when h = 3 inches and s = 10 miles when h = 9 inches (2 <= h <= 15...
  39. Math (Calc) (Differential Equation Solution)

    Some of the curves corresponding to different values of C in the general solution of the differential equation are shown in the graph. Find the particular solution that passes through the point (0, 2). y(x^2+y) = C 2xy + (x^2+2y)y' = 0 How would I start this problem to ...
  40. Math (Calculus II) (Volume Revolution Setup)

    Thanks for the help Steve! Greatly appreciated!
  41. Math (Calculus II) (Volume Revolution Setup)

    Take the area enclosed by the curves y = sqrt(x), y = 1, and x = 4. Rotate it around the line x = 5. Find the volume. While I understand the general problem would call for the shell method ?[a,b] 2*pi*r*h dx With r = 5 - x and h = sqrt(x) - 1 But, what happens say if the ...
  42. Math (Double checking trig identity)

    So tan^2? is where I messed up, thanks Steve!
  43. Math (Double checking trig identity)

    Since sec^2? - 1 = tan^2? I know this is trivial, but I want to make sure I'm doing this right before I apply it to the integral I'm trying to solve... If I have some constant a, (a^2sec?)^2 - (a^2)^2 If I wanted to change this to tan would it be: a^4tan^4?? Any help ...
  44. Math (Calculus II) (Partial Fraction Decomposition

    I'm having trouble trying to solve for the partial fraction decomposition in order to find the integral. ? x / (x^4 - a^4) dx I'm assuming a is some constant in this case. So I factored the denominator to this: (x^4 - a^4) = (x^2 + a^2)(x + a)(x - a) Which turns each ...
  45. Math (Calculus II) (Weird Work Problem Setup Help)

    Correction, I typed the integral wrong! Forgot to include the distance: dF = 53.1(3)(2 - (y/3)) dy dw = dF * Distance W = ? 53.1(3)(2 - (y/3)) (y + 3) dy W = 3106.35 ft-lb
  46. Math (Calculus II) (Weird Work Problem Setup Help)

    I am trying to understand my teacher's example of a Work problem. Cut to the chase here's a picture of the problem: While I understand how to integrate fairly well, I'm still confused on how exactly my teacher set up the work problem...
  47. Math (Integrals) (Volume of Revolution Setup)

    I am supposed to find the area of the region given two boundaries and two functions revolving about the x axis. x = 0 x = pi/2 y = cos(x/2) y = sin(x/2) Graphing those two functions made me select to use the washer method. Therefore, I set my definite integral to this: pi?[0,...
  48. Math (integrals) (Trig Subsititution)

    Woah, I don't think there's a need for i in this problem. This is how I end up doing the problem: ?(sqrt(5)sec^2(?)) / (5tan^2(?) + 5)^(3/2) d? ?(sqrt(5)sec^2(?)) / (5sqrt(5)sec^3(?)) d? Simplifying.. ?(sec^2(?)/ (5sec^3(?)) d? (1/5) ? (sec^2(?) / (sec^3(?)) d? (1/5...
  49. Math (integrals) (Trig Subsititution)

    Find ?1/((x^2+5)^(3/2)) dx I figured this would be a trig substitution problem, so I set x = sqrt(5)tan? and dx = sqrt(5)sec^2(?) d? This would lead to: ?(sqrt(5)sec^2(?)) / (5tan^2(?) + 5)^(3/2) d? But I'm kinda lost on what to do next. I'm used to breaking up the ...
  50. Math (Integrals) (Using given method)

    Thanks! So I was on the right track, but messed up near the ending.
  51. Math (Integrals) (Using given method)

    I would like to solve the ?sin^2(pix) dx Using the given substitution identity: sin^2(x) = (1/2)(1-cos2x) This is what I did so far: ?sin^2(pix) let u = pix du = pi dx (1/pi)?sin^2(u)du Applying the identity is where I'm lost on how to continue further.. (1/pi)?(1/2)(1-...
  52. Math (Integrals) (Using given method)

    ?sin(x)cos(x) dx Using the identity sin(2x) = 2 sin(x) cos(x)?
  53. Math (integrals) (Substitution)

    I am given an integral to solve with given substitution values. I got an answer, but I'm not quite sure if it's correct as an online integral calculator gave a different answer. ? x sqrt(4-x) dx Given that u = 4-x . In this case, x = 4 - u du = -dx Now.. =- ? (4-u)sqrt...
  54. Social Studies

    thank you mwahahaha i got 12/12
  55. Math (Calculus) (Work)

    1.73 ft-lb*****
  56. Math (Calculus) (Work)

    Woops, I didn't convert 1/2 inch to feet. the W equation should be [1/3,9/24], leading to the answer to be around 1/73 ft-lb
  57. Math (Calculus) (Work)

    Six and one-half foot-pounds of work is required to compress a spring 4 inches from its natural length. Find the work required to compress the spring an additional one-half inch. (Round your answer to two decimal places.) This is what I did so far: 4 in = 1/3 ft 6.5 = ?[0,1/3...
  58. Math (Calculus II) (Volume Revolution Setup)

    Thanks! Would we want to use shells of thickness dx and symmetry for (c) as well?
  59. Math (Calculus II) (Volume Revolution Setup)

    Consider the graph of y^2 = x(4-x)^2 (see link). Find the volumes of the solids that are generated when the loop of this graph is revolved about (a) the x-axis, (b) the y-axis, and (c) the line x = 4. I'm just having trouble trying to set up...
  60. P.E

    I'm not Ms. Sue, but I would say B would affect your health in a negative way. When a person is angry, if the person chooses to simply ignore their triggers, it would only makes matters worse over time.
  61. Math (Integrals)

    ? (2x-1)^2 dx could have two answers: a) ((2x-1)^3)/6 + C b) 4/3x^3 - 2x^2 + x + C Now the question is, how are the two answers related? I attempted to answer the question by: "The two answers are related because when finding the derivative of those two different answers...
  62. Math (Integrals) (Basic Integration)

    Yeah I see it, I just tend to overthink way too much than I should so I end up asking obvious questions. My apologies. Thanks so much for the help!
  63. Math (Integrals) (Basic Integration)

    So, why is it that we can't use the easy trick method for the first one? Is it because of the "1" on the numerator that isn't a variable?
  64. Math (Integrals) (Basic Integration)

    I am given two integrals a and b a) ? 1/(1 + x^4) dx b) ? x/(1 + x^4) dx The main difference between the two integrals appears to be the "1" and "x" on the numerators. While they both resembles closely to the basic integration of arctan: ? du/(a^2 + u^2) = ...
  65. Math (Integrals)

    Find the indefinite integral in two ways. ?(2x-1)^2 dx The first way I used was using the power rule and chain rule with substitution. Let u = 2x - 1 du = 2 dx (1/2)? u^2 du (Applying power rule) (1/2) * (u^3/3) + C =(2x-1)^3/6 + C What would be another way of finding the ...
  66. Chemistry

    how much energy is released during the reaction of 2.5l diboron hexahydride with 5.65l chlorine gas?
  67. Science

    C? PsyDAG?
  68. Math (Integrals)

    The area A between the graph of the function: g(t) = 4 - (4/t^2) and the t-axis over the interval [1, x] is: A(x) = ?[1, x] (4 - (4/t^2)) dt a) Find the horizontal asymptote of the graph g. I believe the horizontal asymptote of graph g is g(t) = 4. b) Integrate to find A as a ...
  69. Math (Definite Integrals)

    Should we assume r = 1?
  70. Math (Definite Integrals)

    Sketch the region given by the definite integral. Use geometric shapes and formulas to evaluate the integral (a > 0, r > 0). r ? sqrt(r^2 - x^2) dx -r While I recognize that this looks similar to a circle function, I'm not sure how to graph and evaluate this definite...
  71. Math (Calculus) Integrals

    Can't believe I forgot about that simple rule, thanks for the recall!
  72. Math (Calculus) Integrals

    Evaluate the integral using the following values. 8 ? x^3 dx = 1020 2 8 ? x dx = 30 2 8 ? dx = 6 2 2 ? x^3 dx = ? 2
  73. Math (Calculus II) (Graph approximation)

    Any ideas? Really need help on this one
  74. Math (Calculus II) (Graph approximation)

    Here is the link to the graph of f' in question: I have a hard time trying to answer these kinds of questions when we're only given a graph of f'. a) Approximate the slope of f at x = 4. Explain. I believe the slope of f in this case would be a ...
  75. biology

    HELP PLEASE!!!! How does the outcome of a chemical reaction that absorbs energy differ from one that releases energy?
  76. Science

  77. Math (Stats)

    Well we only use the regression line for predictions if the regression is a reasonable fit for the data, the correlation coefficient is significant, and the data for the predicted values do not go beyond the scope of the data used to estimate the regression. B
  78. Math (Stats)

    In order to predict y-values using the equation of a regression line, what must be true about the correlation coefficient of the variables? A. The correlation between variables must be an x-value of a point on the graph. B. The correlation between variables must be significant...
  79. Alebra 2

    At what point does the terminal side of the angle (5\pi )/(6) in standard position intersect the unit circle?
  80. math

    Elijah made an array of Skittles with 3 rows and 4 columns. Josh made an array of peanuts with 4 rows and 2 columns. Jake made an array of M&M's with 2 rows and 5 columns. What is the total of the candy? -Is it 30?
  81. Math

    The population of bacteria in a petri dish doubles every 12 h. The population of the bacteria is initially 500 organisms. How long will it take for the population of the bacteria to reach 800? Round your answer to the nearest tenth of an hour.
  82. Math-Geometry

    I am having a difficulty with solving proofs, such as triangle proofs for my homework, is there any tips and tricks to be able to solve them?
  83. Math (Octants identifying) *emergency*

    How would I identify a set of coordinates (x, y, z) to be in which octant in a 3d space? Is it just based on the x-value? Depending on the x-value (1-8) used?
  84. random

    this website is so helpful but i am confused on some things 1) the people who answer questions is this their job or are they volunteering to for free and what do they gain out of this 2)do the tutors who answer questions sit at home and answer or at some work place 3) how ...
  85. chemistry

    i thought this was physics
  86. riddle

    The answer is SEX...its old to those whose who have tried it eg married couples but its new to virgins
  87. Math (misleading graphs) (Statistics)

    Thanks so much!
  88. Math (misleading graphs) (Statistics)

    When constructing a graph showing the population of two? countries, an illustrator draws two different people with heights proportional to the populations. Identify a way in which the graph might be misleading. What is the general name for such graphs that use drawings of ...
  89. Math (Stats)

    It's C because class limits and class boundaries cannot be the same!
  90. Math (Stats)

    What is the difference between class limits and class boundaries? A) Class limits are the numbers that separate classes without forming gaps between them. Class boundaries are the least and greatest numbers that can belong to the class. For integer data, the corresponding ...
  91. Language Arts

    Only 13 questions? You are insane. Sure i want some of these answers as well, but that was an insane task to ask. a few is like 1-4, not 13.
  92. Computers (RAM)

    Just giving this a shot, Which of the following statements about RAM are TRUE? Select all that apply. a) Any part of RAM can be accessed at any time. b) RAM is an area of a computer that holds programs and data that are waiting to be processed, to be stored on permanent basis...
  93. Chemistry (percent abundance) *emergency*

    If the average atomic mass of Br is 79.90 amu, what is the percent abundance of each of its isotopes? How would we figure out the isotopes first before we calculate the percent abundance??
  94. Math (calculus) (mean values)

    So basically round up this time, wow!
  95. Math (calculus) (mean values)

    A company introduces a new product for which the number of units sold Ss given by the equation below, where t is the time in months. s(t) = 155(7-(9/(2+t))) a) Find he average rate of change of s(t) during the first year. I got the answer to be 1395/28 b) During what month of ...
  96. Math (optimization) really confused

    Right! Which apparently that isn't the right answer! I did pretty much exactly what @Damon and @Steve but my teacher marked it as wrong. What gives?????
  97. Math (optimization) really confused

    A rectangular fenced enclosure of area 225 square feet is divided half into 2 smaller rectangles. What is the minimum total material needed to build such an enclosure?
  98. Math (related rates) help?

    Hi there, wouldn't we need to use right triangle trig for this problem since it's asking for the rate of the angle? theta? Not completely sure on how to relate that exactly.
  99. Math (related rates) help?

    A 13ft ladder slides down a wall at 2ft/sec when it is 12 ft above the ground. Find the rate at which the angle it makes with the ground changes at this moment?
  100. Chemistry (identifying equations)

    What type of reactions are these? Acid-base? Oxidation/Reduction? Precipitation? 1) Zn (s) + 2 HCl (aq) -> ZnCl2 (aq) + H2 (g) 2) Fe (s) + CuSO4 (aq) -> FeSO4 (aq) + Cu (s) 3) Fe (s) + Cu(NO)2 (aq) -> Fe(NO3)2 (aq) + Cu(s)
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