## IloveCharlie 3 years ago Last problem I need help with! :O It's having to do with finding the identity used in the solution. Please click attached

1. godorovg

hello

2. IloveCharlie

3. IloveCharlie

hi :)

4. godorovg

okay breakdown the problem in your own words

5. godorovg

okay let's start with tan what do we tan is broken down?

6. godorovg

we are working backwards to get to the answer here

7. IloveCharlie

:/ I actually don't really know

8. godorovg

for example tanA= sinA/cosA= SinA/sinC/TanA/ TanB see that

9. godorovg

look at the answers given and compare to what the problem there are clues there

10. godorovg

you still here?

11. IloveCharlie

Yes, sorry. I'm still here! Umm... Let me check

12. IloveCharlie

They all have tan though :/

13. godorovg

yes that is the point because tan is sin/cos

14. IloveCharlie

Yes but how will I know which one is the answer?

15. godorovg

and cos^-1 is 1/cos and sin-1 is 1/sin

16. godorovg

austra I am on the track here? I am rusty so I may be leaving a step out can you help ?

17. Australopithecus

Fun, look at -arccos(3/5) and arcsin(5/13) as just numbers because that is what they are so set x = arcsin(5/13 and y = -arccos(3/5) and see the identity attached

18. Australopithecus

note in respect to the image x and y are theta

19. Australopithecus

well theta1 and theta2 respectively

20. IloveCharlie

Oh I see. To me, it looks like the first option is the correct choice

21. Australopithecus

this problem is just about being able to look up trig identities I dont think you will ever have to memorize these unless you go into majoring mathematics even then I doubt you would ever have to

22. Australopithecus

well there are some trig identites that are important to know but this one I do not believe is used very commonly in early mathematics courses

23. Australopithecus

also im sure you can derive this instead of memorizing it but idk

24. godorovg

hey charlie I was trying to backwards with you,because sometimes it is easier that way. I don't want to mess you up so please let me know .

25. Australopithecus

you are adding in that identity though charlie so it wont be the same

26. Australopithecus
27. IloveCharlie

@godorovg Oh, it's fine. I just didn't quite understand that way but I appreciate your help. @Australopithecus so... the third oone? I'm trying to match up

28. Australopithecus

logically I would think so charlie

29. godorovg

30. Australopithecus

btw unrelated but do you love charlie day from its always sunny in Philadelphia

31. IloveCharlie

Thank you guys! I really appreciate your help!

32. Australopithecus

or is that exclusive to all charlies

33. IloveCharlie

@Australopithecus Oh, no haha Charlie is my dog lol

34. godorovg

lol funny

35. Australopithecus

sorry I meant inclusive :)