Most popular questions and responses by Z32
  1. Calculus

    The population of a region is growing exponentially. There were 40 million people in 1980 (when t=0) and 50 million people in 1990. Find an exponential model for the population (in millions of people) at any time t, in years after 1980. P(t)= Predicted

    asked on October 6, 2009
  2. Physics

    One cubic meter (1.00 m^3) of aluminum has a mass of 2.70 multiplied by 10^3 kg, and the same volume of iron has a mass of 7.86 multiplied by 10^3 kg. Find the radius of a solid aluminum sphere that will balance a solid iron sphere of radius 1.40 cm on an

    asked on August 27, 2010
  3. Physics

    A freezer has a coefficient of performance of 6.30. It is advertised as using 486 kWh/yr. Note: One kilowatt-hour (kWh) is an amount of energy equal to running a 1-kW appliance for one hour. a) On average, how much energy does it use in a single day? I got

    asked on February 16, 2011
  4. Physics

    How much energy does it extract from the outside air with coefficient of performance 3.85? A heat pump has a coefficient of performance of 3.85 and operates with a power consumption of 6.91 x 10^3 W. The first part of the question asked How much energy

    asked on February 16, 2011
  5. Calculus

    A plane flying with a constant speed of 5 km/min passes over a ground radar station at an altitude of 4 km and climbs at an angle of 35 degrees. At what rate, in km/min is the distance from the plane to the radar station increasing 10 minutes later? I got

    asked on September 25, 2009
  6. Calculus

    [Exponential growth & decay] The half-life of radioactive strontium-90 is approximately 29 years. In 1965, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years

    asked on October 6, 2009
  7. Calculus

    Air is being pumped into a spherical balloon so that its volume increases at a rate of 30 cubic centimeters per second. How fast is the surface area of the balloon increasing when its radius is 19 cm? V= 4/3*pi*r^3 S= 4 pi r^2

    asked on September 24, 2009
  8. Calculus

    A street light is at the top of a 17 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 6 ft/sec along a straight path. How fast is her shadow lengthening when she is 30 ft from the base of the pole?

    asked on September 24, 2009
  9. Calculus

    A Norman window has the shape of a semicircle atop a rectangle so that the diameter of the semicircle is equal to the width of the rectangle. What is the area of the largest possible Norman window with a perimeter of 22 feet?

    asked on June 22, 2009
  10. Calculus

    A cylinder is inscribed in a right circular cone of height 8 and radius (at the base) equal to 2. What are the dimensions of such a cylinder which has maximum volume? Radius? Height?

    asked on June 22, 2009
  11. Calculus

    The velocity v(t)= -t^2 + 6t - 8, find the displacement and distance traveled during the time interval [-1,5]?

    asked on December 11, 2009
  12. Calculus

    Find the linearization of f(x)= sqrtx at x=25 and use the linearization to approximate sqrt25.2 This is my math: 5+ 1/10 * (25.2-25) but it's wrong.

    asked on September 27, 2009
  13. Calculus

    A rancher wants to fence in an area of 5189400 square feet in a rectangular field and then divide it in half with a fence down the middle parallel to one side. What is the shortest length of fence that the rancher can use?

    asked on June 22, 2009
  14. Calculus

    Use linear approximation to estimate the amount of paint in cubic centimeters needed to apply a coat of paint 0.03 cm thick to a hemispherical dome with a diameter of 45.000 meters.

    asked on October 13, 2009
  15. Calculus

    If 6075 square centimeters of material is available to make a box with a square base and an open top, find the largest possible volume of the box. Volume=??? cubic cm

    asked on June 22, 2009
  16. Calculus

    Newton's Law of Cooling states that the rate at which an object cools is proportional to the difference in temperature between the object and the surrounding medium. Thus, if an object is taken from an oven at 303 F and left to cool in a room at 74 F, it's

    asked on October 13, 2009
  17. Calculus

    A fence 5 feet tall runs parallel to a tall building at a distance of 7 feet from the building. What is the length of the shortest ladder that will reach from the ground over the fence to the wall of the building? [Hint: Determine the length of a ladder

    asked on June 22, 2009
  18. Calculus

    The manager of a large apartment complex knows from experience that 90 units will be occupied if the rent is 370 dollars per month. A market survey suggests that, on the average, one additional unit will remain vacant for each 5 dollar increase in rent.

    asked on June 22, 2009
  19. Calculus

    Find an overestimate and underestimate that the bug crawls during an hour v= 1 / [2+t]? For time, t, in hours, 0

    asked on November 13, 2009
  20. Calculus

    A fence is to be built to enclose a rectangular area of 280 square feet. The fence along three sides is to be made of material that costs 6 dollars per foot, and the material for the fourth side costs 15 dollars per foot. Find the length L and width W

    asked on November 2, 2009
  21. Calculus

    A spherical snowball is melting in such a way that its diameter is decreasing at rate of 0.2 cm/min. At what rate is the volume of the snowball decreasing when the diameter is 16 cm.

    asked on September 24, 2009
  22. Calculus

    [Implicit Differentiation] (5x-y)^4 + 2y^3 = 258 evaluate y' at the point (1,1)

    asked on September 22, 2009
  23. Calculus

    A projectile is launched at an angle of 60 degrees to the horizontal from 6.5 ft above the ground at an initial speed of 150ft/sec. Assume the x-axis is horizontal, the positive y-axis is vertical (opposite g), the ground is horizontal, and only the

    asked on March 9, 2011
  24. Calculus

    [Integrals] h(x)= -4 to sin(x) (cos(t^5)+t)dt h'(x)=?

    asked on November 21, 2009
  25. Caluclus

    [Mean Value Theorem] f(x)=-3x^3 - 4x^2 - 2x -3 on the closed interval [0,8]. Find the smallest value of c that satisfies the conclusion of the Mean Value Theorem for this function defined on the given interval. I got 8 - sqrt(5696) / -18 = 3.748436059 but

    asked on October 23, 2009
  26. Physics

    An electric power plant that would make use of the temperature gradient in the ocean has been proposed. The system is to operate between 20.0°C (surface water temperature) and 5.00°C (water temperature at a depth of about 1 km). The first question asks

    asked on February 26, 2011
  27. Calculus

    Water is being pumped into an inverted conical tank at a constant rate. The tank has height 9 meters and the diameter at the top is 4 meters. If the water level is rising at a rate of 28 centimeters per minute when the height of the water is 3.5 meters,

    asked on September 25, 2009
  28. Calculus

    At noon, ship A is 10 nautical miles due west of ship B. Ship A is sailing west at 16 knots and ship B is sailing north at 24 knots. How fast (in knots) is the distance between the ships changing at 3 PM? This is what I got but it's not right 28.727

    asked on September 25, 2009
  29. Calculus

    A rectangle is inscribed with its base on the x-axis and its upper corners on the parabola y=2-x^2 What are the dimensions of such a rectangle with the greatest possible area? Width=? Height=?

    asked on June 22, 2009
  30. Physics

    If the stone strikes the ground 65 m away, find the time of flight and initial speed? Vxi = 17.7 m/s Vyi = 8.636 m/s xi = yi = 0, yf = -65.0 m, ay = -g, and vi = 19.7 m/s This is my work so far: trying to find t: 4.9t^2 - 8.636 -65=0 Then I used the

    asked on September 9, 2010
  31. Calculus

    f(x) = 6e^(-5x) ln(x), find f'(3)?

    asked on December 7, 2009
  32. Calculus

    Find the inflection points for f(x) = 12x^5 + 45x^4 - 360x^3 + 7

    asked on October 26, 2009
  33. Calculus

    Evaluate the following limits. lim as x approaches infinity 6/e^x + 7=____? lim as x approaches negative infinity 6/e^x+7=____?

    asked on September 29, 2009
  34. Engineering C source code

    Prompt the user for the inner and outer diameter and thickness of the washer to be entered in cm. Then prompt for the material density in grams per cubic cm (g/cm^3) and the number of washers in the batch. Finally, print out the expected weight in kg. Make

    asked on September 16, 2009
  35. Physics/Engineering

    1. The problem statement, all variables and given/known data I am using a Vishay strain indicator with it hooked up to a strain gage hooked up 1" away from the wall on the solid beam. The beam is .5" by .5", and it is solid. The beam is 16" long and I am

    asked on November 17, 2011
  36. Calculus 3

    Compute the average value of following !@#$%^&tion over the region R? f(x,y)= sinxsiny R= { (x,y): 0 ≤ x ≤pi, 0 ≤ y ≤pi}

    asked on April 15, 2011
  37. Calculus

    Can two level curves of a function intersect; explain?

    asked on March 4, 2011
  38. Philosophy

    Does Bonnie Steinbock think committing adultery is okay or not okay?

    asked on April 29, 2010
  39. Calculus

    Suppose that f(x) = (5x + -2)^(1/2) Find an equation for the tangent line to the graph of f(x) at x=1. Tangent line: y=?

    asked on February 16, 2010
  40. Calculus

    Reflecting the graph calculus problem f(x) = 5^x? reflecting the graph about the x-axis and the y-axis: y=___________ reflecting the graph about the line y = 3. y=__________

    asked on January 27, 2010
  41. Calculus

    Evaluate the integral by interpreting it in terms of areas as 0 goes to 12 |2x - 7|dx? This is my work so far: 2x-7=0 x=7/2 slope = 2; y-int = (0, -7) Area of a triangle is 1/2BH.

    asked on November 15, 2009
  42. Calculus

    What is the absolute max and absolute min of 3+13 |t-8| for -1

    asked on October 20, 2009
  43. Calculus

    What is the derivative of f(x)=5^x log6(x)?

    asked on October 15, 2009
  44. Calculus

    The limit below represents the derivative of some function f at some number a. State such an f and a. lim x-->2 2^x-4/x-2 f(x)=_______ a=_______

    asked on October 2, 2009
  45. Calculus

    Use linear approximation, i.e. the tangent line, to approximate (the 3 is inside the v part if you know what I mean, it's not 3 times sqrt) 3√125.2 as follows: Let f(x) = 3√x. The equation of the tangent line to f(x) at x=125 can be written in the form

    asked on September 28, 2009
  46. Calculus

    Evaluate y' at (2,1) [Implicit differentiation] 5xy-3x-4=0 I got 3/10 and 2/10 but both were wrong.

    asked on September 22, 2009
  47. Calculus

    I wanted to know how you would know that -4x^2 + 2x +90 / x-5 would be able to factor down to (x-5)(-4x-18)/x-5 By looking at -4x^2 + 2x +90 / x-5 , I would never think that it could be factored down to (x-5)(-4x-18)/x-5 How should I approach it so I know

    asked on September 17, 2009
  48. Calculus

    Find the domain of the following function h(x,y) = sqrt(x-9y+5)?

    asked on March 9, 2011
  49. Calculus

    Consider the parabola r(t)=, does the principal unit normal vector point in the + or - y-direction along the curve?

    asked on February 25, 2011
  50. Calculus 3

    Determine whether the lines intersect(have a common point) and if so, find the coordinates of that point? r(t) = < 4t+3, 4t + 2, 6t + 6>, for -infinity < t < infinity R(s) = < s + 2, 3s - 1, -4s + 10>, for -infinity < t < infinity And if r and R describe

    asked on February 18, 2011
  51. Physics

    A crow flies in two successive displacements to a point that is 80 m to the west. Its first displacement is 80 m in a direction θ = 50° west of north. What is the magnitude of its second displacement? What is its direction as measured by the angle θ

    asked on September 2, 2010
  52. Physics

    Junes Verne in 1865 suggested sending people to the Moon by firing a space capsule from a 195 m long cannon with a launch speed of 12.78 km/s. What would have been the unrealistically large acceleration experienced by the space travelers during launch?

    asked on September 1, 2010
  53. Calculus

    What's the derivative of x^2(1- x/6)?

    asked on February 9, 2010
  54. Calculus

    What is the antiderivative of f(x)= 2x^8 + 10x^5 - 8x^4 - 4? I got (2/9)^9 + (10/6)^6 - (8/5)^5 - 4x but it's not right.

    asked on November 5, 2009
  55. Calculus

    Help me simplify this down some more so I can set it to zero and find my critical points. f(x) = x^3 (x+2)^6 f'(x) = x^3 * 6(x+2)^5 + 3x^2 * (x+2)^6

    asked on October 23, 2009
  56. Calculus

    A 25 foot ladder is leaning on a 9 foot fence. The base of the ladder is being pulled away from the fence at the rate of 10 feet/minute. How fast is the top of the ladder approaching the ground when the base is 9 from the fence? [Note: The ladder is

    asked on October 13, 2009
  57. Engineering Materials

    Using mechanics of materials principles (ie. equations of mechanical equilibrium applied to a free-body diagram), derive the following equations. sigma' = sigma cos^2 θ = sigma(1+cos 2θ / 2) and tau = sigma sin θ cos θ = sigma( sin2θ / 2)

    asked on October 8, 2009
  58. Calculus

    If xy=4 and dy/dy=3 then find dx/dt when x=4?

    asked on September 24, 2009
  59. C programming

    The task is to create a c source code program that will name a quadrant when a given coordinate is given. Example: Input Coordinate Pair: 0 5.3 Positive y Axis I just need help on how to start this. I know I have to use if else statements but I'm not sure

    asked on September 23, 2009
  60. Calculus

    [Implicit Differentiation] (6+y)^3 + 4y = x + 55 with y' at (1, -2) y' at (1,-2) =? I got this far but I'm not sure if I'm doing it right: 3(6+y)^2(1dy/dx)+4dy/dx=1

    asked on September 22, 2009
  61. Calculus

    Find the derivative of cos(sqrt(e^(x^3)cos(x)) I got -sin(sqrt(e^(x^3)cos(x))*((sqrt(e^(x^3)cos(x)) Do I just leave the e^(x^3)cosx alone since it's "e" or do I still have the find the derivative for it?

    asked on September 15, 2009
  62. Calculus

    Given that f(x)=x^6h(x) h(-1)=3 h'(-1)=6 Calculate f'(-1).

    asked on September 4, 2009
  63. Calculus

    Evaluate the integral. -2 at the bottom of the integral sign and 7 at the top. f(x)dx f(x)={x if x or equal to 1 I'm not sure how you would apply these two concepts together?

    asked on June 24, 2009
  64. Calculus

    Express the region inside the leaf of the rose r=2sin2? in the first quadrant as an iterated integral over R?

    asked on April 29, 2011
  65. Physics

    (Vectors) If |A x B| = 6.45AB, what is the angle between A and B?

    asked on September 3, 2010
  66. Calculus

    Evaluate the integral from 2/sqrt2 to 4; 1/(t^3 sqrt(t^2-4))?

    asked on September 3, 2010
  67. Calculus

    Estimate the area under the graph f(x)=3x^3 + 5 from x=-1 to x=5 using 12 mid points? I got the right answer for using 6 mid points but what mid points would I use for 12?

    asked on April 20, 2010
  68. Calculus

    Determine the y-coordinate of the critical point for the function where 0

    asked on April 13, 2010
  69. Calculus

    Evaluate the indefinite integral: x^2 / (3-4x^3)^6 I got -1/(60(4x^3-3))^5 but it's not right.

    asked on December 9, 2009
  70. Calculus

    Find the concavity and min and max for f(x) = x*sqrt(x^2+36) defined on the interval [-4, 7]?

    asked on December 8, 2009
  71. Calculus

    f(x) = [3/x^2] - [5/x^7], F(x) is the antiderivative of f(x) with F(1)=0. F(x) = ? I have no idea how to approach this problem. The fractions are scaring me.

    asked on November 6, 2009
  72. Calculus

    F(x) = x^3 / (x-16) is concave up and down on what intervals? I got the derivative to be f' = (x^4 - 48) / (x^2-16)^2 and I found the local min and max but now I need to find where it concaves up and down.

    asked on October 27, 2009
  73. Calculus

    What's the derivative of (x-1)(x-7)^3+10?

    asked on October 20, 2009
  74. Calculus

    Find the derivative of tanh(e^t)

    asked on October 9, 2009
  75. Calculus

    [Linear Approximations and Differentials] I tripled checked my work but I'm still not getting the correct answer. y=3x^2 x=3 & delta x =0.2 I get 3(3.2)^2 - 3(3) = 21.72

    asked on September 27, 2009
  76. Calculus

    Find the Derivative of (7x^2-6)^8(-4x^2-3)^9

    asked on September 15, 2009
  77. Calculus

    Evaluate the definite integral The S thingy has 1 at the bottom and 9 at the top. 4x^2+5 divided by the sqrt of x.

    asked on June 23, 2009
  78. Calculus

    f"(x)=5x+3 and f'(-2)=-3 and f(2)=-5 Find f'(x) and find f(2).

    asked on June 23, 2009
  79. Calculus

    Find the point on the line -5sx+y+3=0 which is the closest to the point (2, 5) (___,___)

    asked on June 22, 2009
  80. Calculus

    f(x)=x*sqrt(x^2+2x+10) + 1*sqrt(x^2+2x+10 defined at the interval [-7,5]. A. f(x) is concave down on the region _,_. B. f(x) is concave up on the region _,_. C. The inflection point for this function is at ____? D. The minimum for this function occurs at

    asked on June 18, 2009
  81. Calculus

    Use logarithmic differentiation to determine the derivative of the function defined by f(x)=x^5(x-3)^9/(x^2+2)^4

    asked on June 15, 2009
  82. Calculus

    What does the arc length formula give for the length of the line r(t)= for 0 ≤ t ≤ 1?

    asked on February 22, 2011
  83. Math

    Solve for t. -45.0 m = (8.636 m/s)t + ½(-9.80 m/s^2)t^2 ?

    asked on September 9, 2010
  84. Calculus

    3 ⌠ 2⌡ (2x^2+5) / x^2 dx =? I got 1.66 but it was wrong.

    asked on November 18, 2009
  85. Calculus

    Estimate the area under the graph of f(x) = 2x^3 + 3 from x= -1 to x=5, first using 6 approximating rectangle and right endpoints, and then improving your estimate using 12 approximating rectangles and right endpoints. When using the left and right

    asked on November 10, 2009
  86. Calculus

    What are the critical points of f(x)= e^x / 3+e^x?

    asked on October 27, 2009
  87. Calculus

    What is the x coordinate of the absolute minimum of 6x + [12/x] when x > 0?

    asked on October 22, 2009
  88. Calculus

    Can someone break this down for me step by step? I'm reviewing for a midterm and got stuck on this problem. 5xy - 3x - 4 = 0 y' at (2,1) I'm not sure where the 5 goes when you apply the product rule to the xy.

    asked on October 15, 2009
  89. Calculus

    Find the derivative of 1/8tan^(-1)(x/8) & (x/2)(sqrt(64-x^2) + 32sin^(-1)(x/8)?

    asked on October 14, 2009
  90. Calculus

    Find the derivative of f(x)=x^2sinh^(-1)(3x)?

    asked on October 13, 2009
  91. Calculus

    [Inverse Functions] f(x)= 5cos(x)sin^(-1)(x) f'(x)=?

    asked on October 7, 2009
  92. Calculus

    F(x)=5e^x - 10 / 24e^x + 12 f^(-1)(x)=? a=? b=?

    asked on October 1, 2009
  93. Calculus

    The expression e^x / e^(4+x) can be written as e^f(x), where f(x) is a function of x, find f(x)?

    asked on September 29, 2009
  94. Science/math

    BCC crystal structure, atomic radius of .1363, and an atomic weight of 95.94g/mol. How would you compute the theoretical density?

    asked on September 15, 2009
  95. Calculus

    If the equation of the tangent line to the curve y=9cosx at the point on the curve with x-coordinate 3pi/4 is written in the form y=mx+b then m=? and b=?

    asked on September 4, 2009
  96. Calculus

    Using the first of these limits, find f'(3) if f(x)=4x^2+4x-2

    asked on September 3, 2009
  97. Calculus

    f(t)=5^x sechx f'(x)=?

    asked on June 15, 2009
  98. Calculus

    If f(x)=6arcsin(x^3) find f'(x)

    asked on June 15, 2009
  99. Calculus

    If f(x)=4-coshx/3+coshx, f'(x)=?

    asked on June 15, 2009
  100. Calculus

    Let f be the function defined by f(x)=2x+11-3e^x If the equation of the tangent line to the graph of f at the point (0,8) is given by y=mx+b then: m=? and b=?

    asked on June 12, 2009