## AmTran_Bus one year ago Trig integral, is it possible to solve this way?

1. AmTran_Bus

So for this I integrated but did not plug in the 4 sec theta. Is that legal?

2. AmTran_Bus

Well, I mean I know it is odd to do, but the basic format of the answer should be correct, right?

3. Loser66

4. AmTran_Bus

Ok. Give me a sec to type.

5. AmTran_Bus

Ignoring the whole 4 sec stuff |dw:1436283835864:dw|

6. AmTran_Bus

I'm still going

7. AmTran_Bus

|dw:1436283910258:dw|

8. Loser66

How can you go from the original one to it? |dw:1436284026292:dw|

9. AmTran_Bus

Oh no. Maybe that is my problem. I forget that sqrt.

10. AmTran_Bus

Wait.

11. AmTran_Bus

Ignore that.

12. Loser66

They assign you to use x =4sec (theta) . Why don't you use it?

13. AmTran_Bus

|dw:1436284192993:dw|

14. AmTran_Bus

I was hoping I could do the base integration first and kinda cheat.

15. AmTran_Bus

|dw:1436284294104:dw|

16. AmTran_Bus

I mean @Loser66 I'm also checking and getting this http://www.wolframalpha.com/input/?i=Integrate+%281%29%2F%28x%5E2sqrt%28x%5E2-16%29%29%2C+x+%3D+4+secant+theta so I kinda think im right?

17. AmTran_Bus

lol http://www.wolframalpha.com/input/?i=Integrate+%281%29%2F%284+secant+theta%5E2sqrt%284+secant+theta%5E2-16%29%29 So yea im pretty confident.

18. AmTran_Bus

internet is awful cutting out

19. Loser66

ok , you are right, but I would like to know how can you turn from sin (sec^- (x/4) ) to that result. To make sure that you can get it by hand, not cheat from wolfram

20. AmTran_Bus

From|dw:1436284669272:dw|

21. Loser66

yes

22. AmTran_Bus

Give me a bit

23. AmTran_Bus

|dw:1436284793682:dw|

24. Loser66

I don't get |dw:1436284904403:dw|

25. Loser66

Hint: $$x = 4 sec (theta) = \dfrac{4}{cos (theta)}$$ $$\sqrt{x^2+16}=4tan(theta) =\dfrac{4sin(theta)}{cos(theta)}$$ see the link?

26. AmTran_Bus

Oh!

27. AmTran_Bus

You aint nothing but a hound dog barking all the time you aint never caught a rabbit and you aint no friend of mine

28. AmTran_Bus

That is not directed at you loser 66, but at calc 2

29. Loser66

hey, what do you mean by "You aint nothing but a hound dog barking all the time you aint never caught a rabbit and you aint no friend of mine"?? are you insulting me?? because I am trying to help you out?? OMG

30. AmTran_Bus

Hahahahahahah nooo!! Elvis man!