## anonymous 3 years ago Find the integral of (cos^2(x))((cosxsin^2n+1)*(pi/2*sinx)+(sinxsin^2n+1)(pi/2*cosx)) from 0 to pi/2

1. anonymous

Input it more clearly.

2. anonymous

$\int\limits_{0}^{\pi/2}\cos ^{2}x(\cos x \sin ^{2n+1}(\frac{ \pi }{ 2 }sinx)+sinxsin ^{2n+1}(\frac{ \pi }{ 2 }cosx))dx$

3. anonymous

Go Wolfram.

4. anonymous

I don't have the first clue on how to use that

5. anonymous
6. anonymous

Wolfram sucks these days :(

7. anonymous

How?

8. anonymous

Thats what happens with all these free awesome programs

9. anonymous

Well, I don't think it even has CAS. I don't use it though.

10. anonymous

Well if you wanna see the steps then you gotta have membership

11. anonymous

Well, I'd expect them to do that.

12. anonymous

Ummm this is an annoying function. @Skip2mylou426 what r u currently studying?

13. anonymous

Wolfram was the best matrix calculator .........

14. anonymous

was?

15. anonymous

Think it's always been Matlab......

16. anonymous

Welll ya Dont have matlab. I used to have mathematica but my comp broke down so dont have it no more :(

17. anonymous

@Skip2mylou426 I think the integral can't be evaluated easily because of the form sin(acos(b))

18. anonymous

@swissgirl Yeah, if you're into coding, you'll fancy Matlab.

19. anonymous

I guess he went to the lou :)

20. anonymous

I was trying to type that monstrosity into Wolfram. Epic fail. It didn't work at all.

21. anonymous
22. anonymous

OMG IK THAT

23. anonymous

It always happens to me

24. anonymous

There is no free CAS engine...........unless you can hack. Otherwise, get your pen and paper.

25. anonymous

wait let me try wolframming it for u

26. anonymous

A little rusty on the calculus. I haven't taken calc in 3 or 4 years unfortunately

27. anonymous

What course are u taking now?

28. anonymous

@swissgirl No point. The integrand has the form of a switch variable 'n' which would leave the answer not numeric, but algebraic........which requires a CAS software.

29. anonymous

It's called Problem Solving. It's a combination of every type of math course that could've possibly been taken.

30. anonymous

FUNNNNNN :)

31. anonymous

haha not quite. He only gives us 1 point per problem solved. All work is required and 500 points are needed to get an A. Class has one month left (halfway done) and I have 178 points right now. KILL ME.

32. anonymous

I don't see the point in putting that into an integral. The integrand can be simplified though....it just looks ugly.

33. anonymous

|dw:1372916840241:dw|

34. anonymous

|dw:1372917002693:dw|

35. anonymous

.........then you start using the identities......

36. anonymous

Ohhhh cooollll Ya I shld have thought of cleaning it up by using identities :)

37. anonymous

Yeah, I'm sure you'd have figured it out eventually. It's just boring to look at.

38. anonymous

so clean it up using identities, then plug in?

39. anonymous

is that a square that cuts off at the end?

40. anonymous

Yes it is

41. anonymous

|dw:1372917328459:dw|

42. anonymous

thanks! think it'll be messy if I don't use identities first?

43. anonymous

Well, depending on how much math you know, yes and no. You might be able to notice the symmetry; and if you can't fiddle with it,

44. anonymous

45. anonymous

just thought i would point that out

46. anonymous

@hobbs978 Thanks. Yours too. No homo.

47. anonymous

48. anonymous

You're welcome. Sorry I couldn't finish it; I'm kinda tired today.

49. anonymous

It's ok, I wish I even remembered how to start it. I feel like a failure.

50. anonymous

hahaha dont feel like one I took 2 semesters of stats earlier this yr and I cant remember pellet Yesterday I was looking at a question and was totally blank. I felt like the biggest failure

51. anonymous

It's funny how the system changes your words by itself. We know what you meant to type instead of "pellet"........

52. anonymous

@Skip2mylou426 http://www.sosmath.com/trig/Trig5/trig5/trig5.html

53. anonymous

So after plugging everything in...I come up with a big fat zero...

54. anonymous

hahahahaha :D Just smile

55. anonymous

Well, zero is an answer...in many cases.

56. anonymous

I may have made a mistake. ugh. ok I'm going to attempt to draw this.. hold on

57. anonymous

|dw:1372918536405:dw|

58. anonymous

ok so the $\cos(0)^3$ is going to be equal to one and then I end up with..

59. anonymous

0

60. anonymous

|dw:1372918796639:dw|

61. anonymous

62. anonymous

Still 0

63. anonymous

Ok that's what I originally had. Sorry, don't hate me

64. anonymous

No, I don't hate you. Stop bringing yourself down. Sure you're an awesome student.

65. anonymous

I'm trying, I really am, but this class is insanely hard. The hardest class in our program is Modern Algebra (which I took last semester), and I thought that was easier than this. I'm at a loss. I don't know what to do.

66. anonymous

Modern Algebra = Abstract Algebra?

67. anonymous

Give or take. Our professor wrote the text for it

68. anonymous

69. anonymous

Ok that is a really hard course.

70. anonymous

71. anonymous

Well, it means you can't find the answers elsewhere......since the professor made them up.

72. anonymous

hahahaha yaaaaaa My abstract algebra course was customized too

73. anonymous

Almost our whole department is like that. The worst thing is that the majority of our professors are research-based and suck at teaching.

74. anonymous

Like most profs out there who cant teach

75. anonymous

I learned a long time ago to never expect a professor to teach well. I just get the syllabus and do my thing.

76. anonymous

Exactly...

77. anonymous

Hmm.. @satellite73 perhaps?...

78. anonymous

that's the issue with this class, he just gives you a bunch of problems with no material to work with

79. anonymous

Get "Engineering Math by KA Stroud" Then go to "Advanced Engineering Math" by anybody.......but Kreyszig........that'll be later because it doesn't explain easy.

80. anonymous

81. anonymous

I probably lack the necessary skills to do that. Can't hurt to try though

82. anonymous

Ya I only do free stuff. I got mathematica for free and all my textbooks in pdf formats

83. anonymous

84. anonymous

@Skip2mylou426 The first book explains quite well. I've used it for HS students, so it should be cool.

85. anonymous

I'll have to check it out soon. Thanks again for your help, I think I'm going to go die now :)

86. anonymous

Stay safe.

87. experimentX

$\frac{2 (1)_{n-1}}{\pi \left( \frac 3 2\right)_{n-1} }$ http://mathworld.wolfram.com/PochhammerSymbol.html