## A community for students. Sign up today

Here's the question you clicked on:

## anonymous one year ago what am i doing wrong here ? Let "picture" Use your calculator to find F″(1)

• This Question is Closed
1. anonymous

2. anonymous

im getting 2

3. anonymous

but these are my only answer choices 12 6 4 1/9

4. anonymous

F'(x) = ln(9x^2) F"(x) = 2/x F"(1) = 2 what am i doing wrong?

5. anonymous

@abb0t @freckles @UsukiDoll

6. UsukiDoll

~_O uhhhhh.. integration is always anti-derivatives no matter what... something is off.

7. anonymous

do you hink the answer choices are somehow wrong?

8. UsukiDoll

ah... try taking the anti-derivative.... then f(b)-f(a) which is f(3x)- f(1) and then evaluate when x = 1?!?!?!!?!?!!!!!!!!!!!!!!!!!!!!!!!!!! this is one strange question

9. UsukiDoll

because whenever I see the integral sign... it's always antiderivative.

10. UsukiDoll

@ganeshie8 any ideas? O_o

11. anonymous

hey @Astrophysics while i have you here can you give me the link to the cool openstudy extension i managed to lose the question where you provided the links :/

12. Astrophysics

Hey sorry I was away, yeah sure just send me a message of what exactly you want. since F'(x) = f(x) we have$F'(x) = \int\limits_{1}^{3x} \ln(t^2) dt$ $F'(x) = \ln(9x^2) - \ln(1)$ F''(x) = f'(x) $F''(x) = \frac{ 2 }{ x }$ $F''(1) = 2$ so this is what you did?

13. anonymous

yes

14. Astrophysics

Mhm that seems right to me haha.

15. UsukiDoll

so somehow the answer choices and whatever you guys did don't match... :/ ~_O! either wrong problem screenshot or wrong answer choices?!!!!!

16. Astrophysics

$\frac{ d }{ dx } \int\limits_{1}^{3x} \ln(t^2) dt = \ln(3x)$ see it basically just cancels out the integral you get what you initially started with, but I don't really trust this integral itself...

17. UsukiDoll

I got the solution.. *grabs problems and throws it away*

18. Astrophysics

I think there is a reason it asks us to use a calculator :P

19. Astrophysics

the ln(1) = 0

20. anonymous

yeah I was thinking that but it truly no longer matters i submitted the answer as 4 and got it wrong , no worries though ill just ask my professor how to do it and see what happens.

21. UsukiDoll

uh huh ln 1 is 0... the way the question is written is odd...too strange for me :P

22. UsukiDoll

fundamental theorem of calculus? eh forget it........ <_<

23. Astrophysics

Ah wait let me see...F'(x) = f(x) $F'(x) = \int\limits_{0}^{3x} \ln(t^2) dt = \ln(9x^2)-\ln(1)$ $F'(x) = \ln(9x^2) \times (3x)' = 3\ln(9x^2)$ I found the mistake...we're suppose to take the derivative of 3x as well..totally missed that part...ok so we have now F''(x) = f'(x) $F''(x) = \frac{ 6 }{ x } \implies f''(1)= 6$

24. Astrophysics

F''(1) = 6*

25. Astrophysics

Fundamental theorem of calculus..bleh

26. anonymous

AAARRRRGGGGHHHH

27. UsukiDoll

wait wtf so when I said Fundamental theorem of Calculus, we got wtf we need?

28. Astrophysics

Yeah haha...can you submit your answer again, does it show the right one?

29. UsukiDoll

da phuc?

30. Astrophysics

haha

31. anonymous

no -_- but it is clearly 6

32. anonymous

damn it all to hell D:

33. UsukiDoll

ffffffffffuuuuuuxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

34. anonymous

ugh oh well , got a B either way

35. Astrophysics

I apologize for the late reply, sorry @Jdosio :\

36. anonymous

its okay, thats what i get when i don't wait for you :(

37. UsukiDoll

ah I see how FTC part 1 would work... but damn too late...

38. Astrophysics

Yeah haha, I just remembered part 1, it's so silly

39. UsukiDoll

then product rule twice... -_- CURSESSSSSSSSSSSSSSSSSSSSSS

40. anonymous

thanks for sticking around so long either way :)

41. UsukiDoll

the variable on f(b) I remember using FTC part 1 all the time on that one... you have to substitute it into the equation (that ln t^2) and then take the derivative of 3x as well

42. Astrophysics

Yup

43. Astrophysics

You have to use the chain rule pretty much...it's weird.

44. UsukiDoll

phuc.. it was my slow thinking -_-

45. Astrophysics

Maybe you can get your mark back, just show the work I guess

46. Astrophysics

To your professor

47. anonymous

its fine its just one question,

48. Astrophysics

Well you won't forget next time either, as I like to say...the struggle is more important than the final answer :)

49. UsukiDoll

|dw:1438769488029:dw| |dw:1438769540072:dw||dw:1438769592473:dw|

50. UsukiDoll

*shoots question*

51. Astrophysics

Haha

52. UsukiDoll

the problem is that FTC 1 is rarely mentioned so there's not a whole lot of practice problems.

53. UsukiDoll

everyone uses f(b)-f(a) part 2

54. Astrophysics

I don't think I've used it since calc 1...I only used it once maybe?

55. Astrophysics

part 2 <3

56. UsukiDoll

ftc 1 is in calc i and only in calc i where as ftc 2 is in calc ii and again in calc iv

57. anonymous

what are you taking now @Astrophysics

58. Astrophysics

I'm going to take ODE :)

59. UsukiDoll

ODEs are fun...

60. Astrophysics

I've taken all the calc courses already, vector calc was ew >.<

61. Astrophysics

But also fun sometimes haha

62. Astrophysics

Towards the end is where I got lost, as we did not have enough time...like I still don't understand Stoke's theorem very well, but don't worry about that stuff right now haha.

63. UsukiDoll

I'm taking Discrete Math this semester to improve my proof writing techniques.

64. Astrophysics

Yeah, that would be a good idea

65. UsukiDoll

gawd I hate proofs... if they are hard >:(

66. anonymous

i really want to take tensor calc, theirs so much of general relativity that is jiberish without it :/

67. Astrophysics

I think it also involves graph theory, from what I've heard is super easy

68. Astrophysics

Yeah haha, I'm actually just taking the math courses that will benefit me in physics right now, al though I would love to take as many math courses I like xD, I'll probably end up doing a lot of them myself after I graduate..

69. UsukiDoll

already got 22 credits worth of upper division math XD.

70. UsukiDoll

which exceeds the BA requirements... BS I think is 39 credits

71. Astrophysics

How many credits per course?

72. Astrophysics

Here it's 3

73. UsukiDoll

3 credits usually, but one of them was 4

74. anonymous

ugh all of that sounds so cool!!! i cant wait to get out of high school -_-

75. Astrophysics

Ahh you're doing this in high school?! I was a total idiot during high school, actually I still am xD

76. UsukiDoll

but be prepared for those dumb general ed requirements. nugh

77. UsukiDoll

I'm doing better in university since I'm taking nothing but maths XD ... and some other requirements that aren't too bad

78. Astrophysics

Lol I hate the core courses, made me take 2 english courses >:( haha.

79. UsukiDoll

yeah I'm like literary analysis isn't going to get you a job mannnnnnnnn!!!!!!!!!

80. Astrophysics

Well at least I learnt how to write a research paper, so that's good I suppppppose.

81. anonymous

i just want to do some bloody physics !! but nothing makes sense without calc 1 and 2 .... so here i am

82. Astrophysics

Lol the physics that requires calculus is annoying at times but very beautiful...

83. UsukiDoll

ehhhhhhhh freelance and technical writing is different XD!!!!! Business writing is useful though

84. Astrophysics

It can be very tedious

85. Astrophysics

Well good luck Jdosio :D, physics and math is awesome, so keep on learning!

86. UsukiDoll

I always die in science subjects T_T. math problems... ok... science problems...OMG GET ME OUT OF HERE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

87. Astrophysics

Calculus is cool because you can derive a lot of the formulas from it, as in kinetmatics but I could show you how to derive those using just a position time graph as well.

88. anonymous

yep, got to admit it can get quite mundane at times but i love it ! :D

89. anonymous

what do you plan on doing after you graduate?

90. Astrophysics

More studying!!! WOO..haha I haven't thought that far as you can see.

91. UsukiDoll

try and get in the MA ...... nothing but pure math ughhhhhh. but an MA in Math is needed to teach at colleges.

92. Astrophysics

Hey, do what ever you like/ enjoy!

93. UsukiDoll

BA in Math is just teaching in High School but at least I'm overqualified for elementary/middle lol... my alma mater wants me to come back.. um no.

94. anonymous

lol XD

95. Astrophysics

Haha, I think I could probably teach a few high school courses as well...chemistry...physics...math maybe

96. Astrophysics

Maybe some biology, been a long while since I've done it though xD

97. UsukiDoll

I wanna go back to the same high school I graduated in. XD. there's air conditioning in that building.

98. UsukiDoll

but I'm trying to aim for teaching at community college/university though.... better benefits.. I think

99. Astrophysics

For sure!

100. anonymous

i feel like teaching is losing though.... im not sure why i mean objectively it sounds great but i just cant see myself ever teaching and enjoying it.

101. Astrophysics

Passing the torch I see, Usuki the great :)))

102. UsukiDoll

teaching is frustrating and not easy... I have to admit it. no wonder some professors get irritated.

103. Astrophysics

Haha, yeah it can be, but still better than a lot of other jobs, but idk I rather just learn right now and not worry about it xD, go with the flow!

104. anonymous

yep, okay well i'm heading to bed , see you guys around :D

105. UsukiDoll

yeah...beats minimum wage X-X

106. Astrophysics

Take care :)

107. UsukiDoll

k night :)

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy