Wednesday, November 25, 2009

Integration

  1. Integrate (1 + 2 sin x ) wrt x with 45 and 0 degrees as bounds8.
  2. Integrate 2x + 3 cos x ) wrt x with 90 and 60 degrees as bounds

These questions has bounds of degrees since trig are involved.

  1. Integrating term by term gives,
  2. integrate 1 wrt x and integrate 2sin x wrt x
  3. this gives x - 2cos x + c
  4. Now the bounds are used to get the required bounded region
  5. Because the curve is a trig, degrees or radians can be used
  6. In this case the curve has a trig part and a polynomial part so radians must be used

63 comments:

  1. (1 + 2 sin x )
    1x+ 2 +cos x
    1x-2cosx
    wrtx 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  2. 2x + 3 cos x
    integration=
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  3. Question on integration (open to anyone)

    Integrate 7 + x with respect to x

    ReplyDelete
  4. Could you also please explain how you arrived at your answer

    ReplyDelete
  5. Open question
    What are the two types of integrals and to which one do we add a constant of integration to our final answer ? Could someone please enlighten us ?

    ReplyDelete
  6. Open question
    If for example we asked to find the area of a curve between the points x = 2 and x = 5 which one is the upper limit and which is the lower limit and why is this so ? Someone please enlighten us ?

    ReplyDelete
  7. Open question
    Integrate (2x^2 - x^3) between x = 4 and x = 1

    ReplyDelete
  8. Could someone please explain step by step how to plot a quadratic graph . What do you do first?

    ReplyDelete
  9. green lantern why didnt you change degrees to radians

    ReplyDelete
  10. you only change from degrees to radian only if the ask or the question needs u to convert to readians.

    ReplyDelete
  11. 1. 1x+ 2 +cos x
    1x-2cosx
    wrt x 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  12. 2. 2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  13. to answer reaper..
    the first question
    the integral of 7+x
    is
    7x+x^2/2

    ReplyDelete
  14. to reaper..
    when the limits are given the upper limit is the larger number and the lower limit is the smaller of the 2 numbers..
    like the upper limit is 5
    and lower limit is 2

    ReplyDelete
  15. to answer reaper question..
    the integration of (2x^2-x^3) with limits of 4 and 1
    is
    the integration is
    2x^3/3-x^4/4
    the upper limit is 4
    and
    lower limit is 1
    so
    [2(4)^3/3-(4)^4/4)-(2(1^3/3-(1)^4/4}
    (42.67-64)-(0.66-.25)
    -21.33)-(.41)
    -21.74
    area cannot be negative
    this only means that the area found is under the x-axis.
    the are is 21.74

    ReplyDelete
  16. to reaper
    how to draw a quadric graph.
    1. to draw a graph u must have the roots which are two point on the graph.
    2. the shape could only be two shapes
    3. locate the coefficient of the x^2 value.
    4. if it is +ve then u will have a valley graph..with a min point. if _ve then u will have a hill with a max point.
    5.to find the two point either by factorizing or if the equation cannot be factorize then use the quadratic formula.
    when u have gotten the 2 point the plot then and draw the graph...

    ReplyDelete
  17. 2x + 3 cos x
    integration=
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  18. This comment has been removed by the author.

    ReplyDelete
  19. 1)

    (1 + 2 sin x)
    1x+ 2 + cos x
    1x-2cos x

    wrtx 45 degrees
    1(45) + 2 cos 45
    45 + 2(.707)
    45 + 1.414
    16.414 deg

    ReplyDelete
  20. to integrate(1 +2 sin x)
    (1+2sinx)
    1x+2+cosx
    1x-2cosx
    wrt(45degrees)
    1(45)+2cos45
    45+2(.707)
    45+1.414
    46.414degrees

    ReplyDelete
  21. This comment has been removed by the author.

    ReplyDelete
  22. This comment has been removed by the author.

    ReplyDelete
  23. Hi Green Lantern can u plz explain #1 & #2.

    ReplyDelete
  24. 1. 1x+ 2 +cos x
    1x-2cosx
    wrt x 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  25. 2x + 3 cos x (integrating)

    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  26. for ques 1
    1x+ 2 +cos x
    1x-2cosx
    wrt x 45°
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414°

    ReplyDelete
  27. 2x + 3 cos x
    integrating that gives=
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  28. 1)
    the question is 1 + 2 sin x and we have to integrate this. the integral of 1 is x and the integral of 2 sin x = - 2cosx.
    so the expression is now:
    x - 2cosx

    the bounds are 45 degrees and 0 degrees.
    [(45) - 2cos45] - [(0) - 2cos(0)]
    [45 - 2(0.707)] - [- 2(1)]
    [45 - 1.414] - [-2]
    43.6 - (-2)
    43.6 + 2
    45.6 degrees

    ReplyDelete
  29. 2)
    2x + 3cosx
    integrating,we get:
    2x^2/2 + 3sinx
    x^2 + 3sinx

    the bounds given are 90 degrees and 60 degrees.
    since there is a polynomial part as well as a trig part, we have to convert to radians.

    1 rad = 180 degrees
    therefore, 1 degree = 1/ 180 rad
    therefore 90 degrees= 1/180 * 90
    = 0.5 rad
    therefore 60 degrees= 1/180 * 60
    = 0.33 rad

    x^2 + 3sinx
    substituting x for the limits:

    [0.5^2 + 3sin(0.5)] - [0.33^2 + 3sin(0.33)]
    [0.25 + 0.0262] - [0.1089 + 0.0173]
    [0.2762] - [0.1262]
    0.15 sq units

    ReplyDelete
  30. in the previous post, the answer is 45.6 sq. units and not degrees as integration is used to calculate area...sorry bout that...

    ReplyDelete
  31. RE:Open question
    If for example we asked to find the area of a curve between the points x = 2 and x = 5 which one is the upper limit and which is the lower limit and why is this so ? Someone please enlighten us ?

    ok reaper. remember when miss was saying that wen we integrate from a limit, it gives us the area to the left of that limit until infinity?
    that is the reason we have two limits. Green Lantern was right in saying that the larger of the two values is the upper limit and the smaller is the lower limit.

    however the explanation is that since you get the area to the left of the limit til infinity, if you integrate from another limit as well, you also get the area to the left of that limit until infinity.the reason we find the difference between the two areas is that this gives the area that we really want, which is the area under the curve. catch? if not u can ask for more clarification...hope this is sufficient.

    ReplyDelete
  32. 2)
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  33. (1 + 2 sin x )
    1x+ 2 +cos x
    1x-2cosx
    with respect to x 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    46.414 deg

    ReplyDelete
  34. 2x + 3 cos x
    integration =
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  35. 1 +2sinx
    1x+2+cosx
    1x-2cosx
    when it is 45 degrees
    1(45)+2cos 45
    46.414 degrees

    ReplyDelete
  36. 1 + 2sinx
    1x-2cosx when 45 degrees 1(45)+2cos 45=46.414

    ReplyDelete
  37. mommy can you teach over integration tomorrow plsssssss

    ReplyDelete
  38. 1)
    (1 + 2 sin x )

    1x+ 2 +cos x

    1x-2cosx

    wrtx 45 degrees

    1(45) +2 cos 45

    45+2(.707)

    45+1.414

    16.414 deg

    ReplyDelete
  39. 2)
    2x^2/2 +3 sin x

    x^2+3sinx

    between 90 and 60

    x^2+3sin x

    x^2+3sin90

    x^2+3

    ReplyDelete
  40. ∫(1 + 2 sin x)dx
    x+ 2 + cos x
    x-2cos x
    45 degrees=Π/4
    wrt to 0
    1(Π/4) + 2 cosΠ/4
    -1.214

    wrt to 0
    1(0)-2cos(0)
    -2

    -1.214-(-2)
    =1.214 rad

    ReplyDelete
  41. help please!!!!!!
    i don't understand integration......can sum1 please explain.....

    ReplyDelete
  42. @ absolutely fantastic i don't understand how you arrived at your answer.....please explain....thanks

    ReplyDelete
  43. 1+2sinx 45,0 as bounds

    [x-2cosx]

    [π/4-2cos(π/4)]-[0-2cos0]

    π/4-1.414+2

    π/4-0.586

    ReplyDelete
  44. 2x + 3 cosx 90,60 as bounds

    2x^2 + 3sinx

    [2(π/2)^2 + 3sin(π/2] - [2(π/3)^2 + 3sin(π/3)

    4.935 + 3 + 2.193 + 2.598

    12.726

    ReplyDelete
  45. (1 + 2 sin x )
    1x+ 2 +cos x
    1x-2cosx
    wrtx 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  46. 1)
    (1 + 2 sin x )

    1x+ 2 +cos x

    1x-2cosx

    wrtx 45 degrees

    1(45) +2 cos 45

    45+2(.707)

    45+1.414

    16.414 deg

    ReplyDelete
  47. (1 + 2 sin x )
    1x+ 2 +cos x
    1x-2cosx
    wrtx 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  48. 2x + 3 cos x
    integration=
    2x^2/2 +3 sin x
    x^2+3sinx
    between 90 and 60
    x^2+3sin x
    x^2+3sin90
    x^2+3

    ReplyDelete
  49. (1 + 2 sin x )
    1x+ 2 +cos x
    1x-2cosx
    wrtx 45 degrees
    1(45) +2 cos 45
    45+2(.707)
    45+1.414
    16.414 deg

    ReplyDelete
  50. integration i am little bewildered about!!!

    ReplyDelete
  51. i need some clarification and explanation!!!!

    ReplyDelete
  52. 1)
    1+2sinx
    integration
    1x+2cosx
    45 degrees
    1(45)+2cos45
    45+1.414
    46.414

    ReplyDelete
  53. question on number 2)2x+3cosx

    how come u didn't subs. 90 degrees into x^2
    2x^2/2+3sinx
    (anyone)

    ReplyDelete
  54. number (1)
    1+2sinx 45,0 as bounds

    [x-2cosx]

    [π/4-2cos(π/4)]-[0-2cos0]

    π/4-1.414+2

    π/4-0.586

    ReplyDelete
  55. number (2)
    2x + 3 cosx 90,60 as bounds

    2x^2 + 3sinx

    [2(π/2)^2 + 3sin(π/2] - [2(π/3)^2 + 3sin(π/3)

    4.935 + 3 + 2.193 + 2.598

    12.726

    ReplyDelete
  56. 1+2sinx 45,0 as bounds
    [x-2cosx]
    [π/4-2cos(π/4)]-[0-2cos0]
    π/4-1.414+2
    π/4-0.586

    ReplyDelete
  57. 2x + 3 cosx 90,60 as bounds
    2x^2 + 3sinx
    [2(π/2)^2 + 3sin(π/2]-[2(π/3)^2 + 3sin(π/3)
    4.935 + 3 + 2.193 + 2.598
    =12.726

    ReplyDelete
  58. 1). (1+2sinx)

    the integral of that is x-2cosx

    using bounds 45 and 0 degrees

    [45-2cos45]-[0-2cos0]
    [43.59]-[-2]
    43.59+2
    45.49

    ReplyDelete
  59. 2). (2x+3cosx)

    the integral of that is x^2+3sinx

    using bounds 90 and 60 dgrees
    [(90)^2+3sin90]-[(60)^2+3sin60]
    [8100+3]-[3600+2.60]
    8103-3602.6
    4500.4

    ReplyDelete
  60. Integrate (1 + 2 sin x ) wrt x with 45 and 0 degrees as bounds.
    =1x - 2cosx
    bounds 45 and 0 = 45 - 2cos 45 - 0-2cos0
    = 43.59 - (-2)
    = 45.59

    ReplyDelete
  61. question 1

    the intergral of 1+2sinx dx

    =[x-2cosx] limits 45 and 0

    =[45-2cos45]-[0-2cos0]

    =[43.586]-[0]

    =43.586

    ReplyDelete
  62. question 2

    the integral of 2x+3cosx dx

    =[x^2+3sinx] limits 90 and 60

    =[90^2+3sin90]-[60^2+3sin60]

    =[8130]-[3602.6]

    =4527.4

    ReplyDelete
  63. question 2

    integral of 1 dx

    =x

    integral of 2sinx dx

    =-2cosx

    =x-2cosx+c

    ReplyDelete