oobleck

Popular questions and responses by oobleck
  1. Calculus - Integration

    I ran across this one the other day. See what you can make of it. Find the integral of ecosxsinx - (sinx+cosx)esinx+cosx ----------------------------------------- esin2x-2esinx+1

    asked on May 22, 2019
  1. math

    (9.71-9.8)/9.8 = -0.00918 * 100% = -0.918%

    posted on June 2, 2020
  2. Physics

    consider the height of the ball. y = v sinθ t - 16.1t^2 what is v? no idea, but we do know that with a constant horizontal speed of v cosθ, it flew 196 feet. so, t = 196/(v cosθ) Plug that in, and you just have to solve y = 196 tan30.3° - 16.1t^2 =

    posted on June 2, 2020
  3. Chemistry

    PV/T is constant, so you want 4.81V/(91.60+273.15) = 1*(21.5*22.4)/273.15

    posted on June 2, 2020
  4. precal

    it is discontinuous, because the denominator is zero at x = -2, -5

    posted on June 2, 2020
  5. Calculus

    Just treat y as a constant. Then apply the quotient rule

    posted on June 2, 2020
  6. mathemathics

    kinda missing some information, eh? If you know how to find the volume and area of a prism, though, it should not be too hard.

    posted on June 2, 2020
  7. MATH

    well, 18 is the minimum 42 is the maximum the sum of six odd numbers must be even So only 26 is left.

    posted on June 2, 2020
  8. math

    nope. 2 for Jeff 3 for Maria so, Jeff got 2/5 of the shells, not 2/3. This illustrates the difference between probability (2/5) and odds (2:3)

    posted on June 2, 2020
  9. math

    one which is just a multiple of another 2/3 = 4/6 = 10/15 etc. They are all equivalent.

    posted on June 2, 2020
  10. Mathematics

    the midpoiint of the diameter (2,3) is the center of the circle. So the equation is (x-2)^2 + (y-3)^2 = r^2 r is half the length of the diameter, so ...

    posted on June 2, 2020
  11. history

    whining won't get you help any faster. While you're waiting, have you done some googling?

    posted on June 2, 2020
  12. Chemistry

    10 days * 2doses/day * 10mL/dose * 50mg/mL = 10*10*2*50 mg

    posted on June 2, 2020
  13. mathematics

    #1 see your previous post #2: sin(cos^-1(1-x)) Let cosA = 1-x Draw a triangle with angle A such that the adjacent leg is (1-x) and the hypotenuse is 1. Then the opposite leg is √(1 - (1-x)^2) = √(2x-x^2) Now you can tell sinA. #3. Use the law of sines.

    posted on June 2, 2020
  14. Mathematics

    r/b = 2/3, so r = 2/3 b (r-3)/b = 3/5 5(r-3) = 3b 5(2/3 b - 3) = 3b now finish solving for b

    posted on June 2, 2020
  15. mathematics

    sqrt(6-3x)-2=0 sqrt(6-3x) = 2 6-3x = 4 so, what do you think?

    posted on June 2, 2020
  16. Mathematics

    hav B = 0.2351

    posted on June 2, 2020
  17. Mathematics

    = t(8-t)

    posted on June 1, 2020
  18. math

    75% and 25% are multiples of 1/4 So how many multiples of 4 are there in 1000?

    posted on June 1, 2020
  19. math

    .75 * 100 = 75

    posted on June 1, 2020
  20. Mathematics

    You have two pairs of triangles, right? You have the base and height, so just do the math.

    posted on June 1, 2020
  21. Math

    well, it is clear that you keep multiplying by 4, right? That only leaves one choice

    posted on June 1, 2020
  22. Precalculus

    y = (t-3)^2 - 4 = t^2-6t+5

    posted on June 1, 2020
  23. Physics

    did it burst into flame?

    posted on June 1, 2020
  24. maths

    since f(x) is defined for x=2, it is just 2^2+1 = 5 for x>2, the limit would be (2-3)^2 = 1 Since the limits are not the same, you cannot have both f(x)={x²+1 if x≤2 {(x-3)² if x≥2 it must be either f(x)={x²+1 if x≤2 {(x-3)² if x>2 or f(x)={x²+1

    posted on June 1, 2020
  25. mathematics

    you want 0.095 to be 9.5x10^___ how many places to the right did you shift the decimal point?

    posted on June 1, 2020
  26. Maths

    (2W)(2L) = 4WL 4 times the area, 4 times the time.

    posted on June 1, 2020
  27. math

    probably only a hundred books or so, and 100/4 = 25 So, a reasonable breakdown would be 3/4 = 75/100 non-fiction

    posted on June 1, 2020
  28. Mathematics

    as written, it is not true. I think you meant (1-sin2x)/cos2x = (1 - 2sinx cosx)/(cos^2x - sin^2x) = (cos^2x - 2sinx cosx + sin^2x)/(cos^2x - sin^2x) = (cosx-sinx)^2 / ((cosx-sinx)(cosx+sinx)) = (cosx-sinx)/(cosx+sinx) = (1-tanx)/(1+tanx) = tan(π/4 - x)

    posted on June 1, 2020
  29. Precalculus

    it hits the ground when the height is zero, right? So just solve 6 + 95 sin25° t - 16t^2 = 0

    posted on June 1, 2020
  30. Precalculus

    Assuming down the alley toward the pins is the +y direction, then (x,y) = 7*1.5 * (cos87,sin87)

    posted on June 1, 2020
  31. precalculus

    note that x^2+y^2 = 9 now review how angles are graphed in polar coordinates.

    posted on June 1, 2020
  32. Math

    find the limit of (f(x+h)-f(x))/h = [((x+h)^2 - 3(x+h) + 5) - (x^2-3x+5)]/h You should wind up with 2x-3

    posted on June 1, 2020
  33. math

    compare 7:5 to 40:30 or, 70:50 to 4:3 the size of the ratio says nothing about the total quantities

    posted on June 1, 2020
  34. math

    alternate signs as in -,-,+,+,-,-,+,+,... and just keep multiplying by 4 a_n = (-1)^(1+[(n-1)/2] * 6 * 4^(n-1) where [x] is the greatest integer (floor) function

    posted on June 1, 2020
  35. math

    r:b = 5:6 b:g = 3:4 = 6:8 r:b:g = 5:6:8 = 10:12:16 and so on there are many ways to do this, just multiplying those three numbers by any desired value

    posted on June 1, 2020
  36. Mathematics

    K/4650 = 3/5 now just solve for K

    posted on June 1, 2020
  37. chemistry

    M = mol/L so you are correct.

    posted on May 31, 2020
  38. Science

    compare 0.12 * 150 with 0.15 * 120 And a question cannot be true or false -- it is a question.

    posted on May 31, 2020
  39. math

    oops. no math is required. I figured how many slices were eaten... There were 12 slices, and 5 are left. So, 5 bags needed.

    posted on May 31, 2020
  40. math

    12/12 - 5/12 = ___/12

    posted on May 31, 2020
  41. math

    Matt's score ... m 23 less than m ... m-23 is ... = and so on.

    posted on May 31, 2020
  42. math

    a) your answer is correct, but you have an extra paren in lin e 3. (1^2 - (3(1)+5)/(1-2) should be (1^2 - 3(1) + 5)/(1-2) b) is also correct

    posted on May 31, 2020
  43. Algebra

    (a^2a^4)÷a^−3 = (a^2a^4)*a^3 = a^6*a^3 = a^9 a/(a^2a^3)^4 = a/(a^5)^4 = a/a^20 = a^-19 a^9÷a^-19 = a^9 * a^19 = a^28

    posted on May 31, 2020
  44. Mathematics

    If you don't have a protractor, it is easy to construct the 105° angle, since 105=90+15 So just make a 90° angle make a 60° angle and bisect it twice to get the 15° angle Then add them together.

    posted on May 31, 2020
  45. Math

    Hard to parse your table. Are the first six values x and the last 5 y? Why are there not 12 values? As a first guess, I'd say the next x is -4, since the differences go -12, -6, -12, -6 The y differences go -12, 4, -12, 4 The extra ? stumps me.

    posted on May 31, 2020
  46. Mathematics

    (a) less improvement as just a number of points, or as a percentage? points: 30 > 18 percent: 18/30 > 1/2 30.60 = 1/2 (b) E+M-(E&M) = U-7 38+M-9 = 63 Now you can answer the questions.

    posted on May 30, 2020
  47. mathematics

    well, S720E is just S so what is 20° less than S? S = 180°, so 180-20 = 160°

    posted on May 30, 2020
  48. math

    c+a = 292 1.50c + 4.00a = 838.00 Now just solve for c and a.

    posted on May 30, 2020
  49. mathematics

    p= 1.8cm If you meant P, then use the law of cosines p^2 = q^2 + r^2 - 2qr cosP

    posted on May 30, 2020
  50. mathematics

    recall the law of sines sinA/a = sinB/b Once you have A, then C = 180-(A+B)

    posted on May 30, 2020
  51. mathematics

    just add or subtract 180°, so that your answer is between 0 and 360°

    posted on May 30, 2020
  52. Physics

    I think I'd go with E. google turned up the following explanation: Note that as a group, the unsaturated fatty acids have lower melting points than the saturated fatty acids. The reason for this phenomenon can be found by a careful consideration of

    posted on May 30, 2020
  53. Algebra

    a_1 = 1/2 a_2 = 3/4 a_3 = 21/16 Now, since x^2+x > x^2 and a_n > 1 for n > 2 and (x^2+x/x) = x + 1 a_4/a_3 > a_3+1 = 37/16 > 3/2 The a_n are always increasing, and since a_3 >3/2, a_n > 5/2 for all n > 3 And, a_(n+1)/a_n = a(n) + 1 > 3/2 So, even though

    posted on May 30, 2020
  54. Mathematics

    #1) 181+142+117-(75+60+54)+x = 200 I suspect a typo.

    posted on May 30, 2020
  55. Math

    800 cos39° you decide whether that's east or west. It won't be both...

    posted on May 30, 2020
  56. Math

    depends on the size of the walls ... double the area and divide by 100 to find the quarts needed (round up)

    posted on May 30, 2020
  57. algebra

    a+b = 2 a-b = -4 add the two lines and you get 2a = -2 and the rest is easy.

    posted on May 30, 2020
  58. math

    again?

    posted on May 30, 2020
  59. Algebra

    In vertex form, f(x) = a(x-h)+k where the vertex is at (h,k) f(x)=2/5x^2-4x+14 = 2/5 (x^2 - 10x) + 14 = 2/5 (x^2 - 10x + 25) + 14 - 2/5 * 25 = 2/5 (x-5)^2 + 4 So the vertex is at (5,4) as above

    posted on May 29, 2020
  60. Algebra

    Just as a shortcut, for nPk, start at n and count down for k factors. For example, 9P3 = 9*8*7 for combinations, do the same, but divide by k factors counting up 12C4 = (12*11*10*9) / (1*2*3*4) Note that this makes it clear why you never have to go more

    posted on May 29, 2020
  61. physics

    v = fλ = λ/t so you are correct

    posted on May 29, 2020
  62. Algebra

    #1: 6/20 * 5/19 * 4/18 = 1/57 #2 chance of (brown,orange,orange) = 5/20 * 2/19 * 1/18 but the brown can happen in any of three places, so the final probability is 3(5/20 * 2/19 * 1/18) = 1/228 Too bad you couldn't be bothered to show your work - just

    posted on May 29, 2020
  63. Math

    well, that would be 40% of 26, right? 0.40 * 26 = ____

    posted on May 29, 2020
  64. Math

    looks good to me.

    posted on May 29, 2020
  65. Math

    rats - y = -√33

    posted on May 29, 2020
  66. Math

    in QIII, x

    posted on May 29, 2020
  67. Math

    your calculations are correct, but that is not C

    posted on May 29, 2020
  68. math

    3 points for every field goal points depends on goals, right?

    posted on May 29, 2020
  69. math

    no diagram

    posted on May 29, 2020
  70. math

    divide both sides by nR

    posted on May 29, 2020
  71. math

    well, how many weeks is that? multiply that by 1/3 * $25

    posted on May 29, 2020
  72. Algebra

    since (a+b)^2 = a^2 + 2ab + b^2, we have (2√5+3√7)^2 = (2√5)^2 + 2(2√5)(3√7) + (3√7)^2 = 4*5 + 12√5√7 + 9*7 = ...

    posted on May 29, 2020
  73. Calculus/Vectors

    recall that T = rFsinθ so plug in your numbers

    posted on May 29, 2020
  74. mathematics

    They all say the same thing (D only if you already know A or B or C) I like C simpler than fractions, and the raw numbers in D really don't convey any information.

    posted on May 29, 2020
  75. math

    v = dy/dx = dy/dt / dx/dt = (e^t-2cost)/(1/t + 3t^2) a = dv/dx = dv/dt / dx/dt = [(e^t+2sint)(1/t + 3t^2) - (6t - 1/2)(e^t-2cost)]/(1/t + 3t^2)^3 This is just a stupid exercise -- needlessly complicated.

    posted on May 29, 2020
  76. Algebra

    again? 4√6/√30 * √30/√30 = 4√180/30 = 4*6√5/30 = 4√5/5 or 4√6/√30 = 4√6 / √5√6 = 4/√5 = 4√5/5

    posted on May 29, 2020
  77. Physics

    net force is the sum of all the forces acting on the object. Then, of course, F = ma if there is a nonzero net force, the object will undergo an acceleration.

    posted on May 29, 2020
  78. Physical Science

    assuming the pressure remains the same, V1/T1 = V2/T2 not sure how going from 1.2 cm^3 to 200 cm^3 is a decrease, though ...

    posted on May 29, 2020
  79. Maths

    red: P(male) = 1/3 blue: P(female) = 1/3 so, 1/9 that he will get both the needed gp's.

    posted on May 29, 2020
  80. math

    HCF(64,124) = HCF(4*16,4*31) = 4 LCM(64,124) = 64*124 / HCF(64,124)

    posted on May 29, 2020
  81. pre-calculus

    use the law of sines: b/sinB = a/sinA

    posted on May 29, 2020
  82. mathematics

    (h-1.7)/25 = sin30°

    posted on May 29, 2020
  83. Trig

    tan>0 and cos

    posted on May 28, 2020
  84. Algebra

    See if you can show that a_(n+1) > 3/2 a_n Having that, now you know that 1/(a(n+1)+1) < 1/a(n+1) < 2/3 1/a_n That means that each term of the sum is less than the corresponding term in the geometric sequence a = 2/3 r = 2/3 The infinite sum of that is

    posted on May 28, 2020
  85. science

    what kind of magazine?

    posted on May 28, 2020
  86. algebra

    red = a white = a/2 total = a + a/2 = 3/2 a

    posted on May 28, 2020
  87. Calculus

    a×b ⊥ a and b c = {3, 5, -4}×{-3, 1, -5} = {-21,27,18} and of course, -c is also ⊥ to a and b

    posted on May 28, 2020
  88. Calculus

    just plugging the various values for n, I get sum(1..∞) = ln 2 = 0.69314718 so we want the sum to lie between 0.69304 and 0.69324 sum(1..9) = 0.7456 sum(1..99) = 0.6981 sum(1..999) = 0.6936 sum(1..9999) = 0.693197

    posted on May 28, 2020
  89. Calculus

    so, did you use the table? It will probably provide a reduction formula, such as ∫x^n e^ax dx = 1/a x^n e^ax - n/a ∫ x^(n-1) e^ax dx this is achieved using integration by parts. So, going through that three times gives you (1/9 x^3 - 1/27 x^2 + 2/243 x

    posted on May 28, 2020
  90. math

    P: (x,y) → (x,b-(y-b)) = (x,2b-y) Q: (x,y) → (x,2a-y) P∘Q: (x,y) → (x,2a-(2b-y)) = (x,2a-2b+y)

    posted on May 28, 2020
  91. Algebra

    for any x, x + 6x = 7x You just happen to have x = sqrt5

    posted on May 28, 2020
  92. Algebra

    I assume you mean y = 1/2 x - 3 So, just pick two values for x, say, 0 and 1, and figure what y is for each.

    posted on May 28, 2020
  93. Maths

    let P = (m,15/8 m) Q = (n,3/10 n) Then since PR=QR, (8-m)^2 + (6 - 15/8 m)^2 = (8-n)^2 + (6 - 3/10 n)^2 and, since the slope of PR = slope of QR, (15/8 m - 6)/(m-8) = (3/10 n - 6)/(n-8) Solving for m and n, we have m = 32/7, n = 80/7 Plugging that into the

    posted on May 28, 2020
  94. Math

    yes. after removing the parentheses, that would be the same as adding -7x+12-3x^2

    posted on May 28, 2020
  95. geometry

    adjacent angles are supplementary - they add to 180°

    posted on May 28, 2020
  96. math

    1030/95 = ____

    posted on May 28, 2020
  97. Algebra

    just subtract 4 from each element of the domain

    posted on May 27, 2020
  98. mathematics

    I'd guess non-negative integers (up to some reasonable maximum)

    posted on May 27, 2020