## babydoll332 3 years ago Find the exact value of cot-1(1). please step by step :)

1. Brittni0605

what is cot using sin and cos?

2. babydoll332

wait wat? explain... please

3. Brittni0605

Do you know what cot means?

4. babydoll332

cotangent

5. Brittni0605

Yes, but what is cotangent?

6. babydoll332

sin/tan

7. babydoll332

cos/sin

8. Brittni0605

Its cos/sin

9. Brittni0605

|dw:1352671301171:dw|

10. babydoll332

idk wat to do next...

11. Brittni0605

|dw:1352671590676:dw|

12. babydoll332

pi

13. Brittni0605

No.

14. Brittni0605

|dw:1352671674439:dw|

15. babydoll332

pi/2

16. Brittni0605

No, what is cos in general?

17. zordoloom

Do you still need help with this?

18. babydoll332

yess

19. Brittni0605

cos is x sin is y

20. babydoll332

wow ok im sorry u have to do the basic with me

21. Brittni0605

|dw:1352671946433:dw|

22. babydoll332

ok

23. babydoll332

i understood that

24. Brittni0605

OK, good.

25. zordoloom

Allright, So you are given cot^-1(1) The cot^(-1) means to find the angle where cot is 1 Cot is also (cos/sin) So if you look at the unit circle, where does cos equal 1? So cos is 2pi at 1 and sine is pi/2 at 1 If you put 2pi/pi/2 you get pi/4 So cos^-1(1) is pi/4

26. Brittni0605

You can follow @zordoloom, but im not sure what he's doing. So your choice.

27. babydoll332

how would i get 2pi/pi=4pi

28. Brittni0605

It doesnt equal 4pi. That would equal 2

29. babydoll332

If you put 2pi/pi/2 you get pi/4

30. Brittni0605

No, you get 1.

31. babydoll332

and where do i find 1 on the unit circle

32. Brittni0605

|dw:1352672476549:dw|

33. babydoll332

i know its 45degree but idk how?

34. Brittni0605

gimme a sec

35. babydoll332

like idk how how cos 1 = pi/4 i get how to get it but not how u get thru the unit circle

36. Brittni0605

what are the coordinates of pi/4 on the unit circle?

37. babydoll332

no how he got this

38. babydoll332

So if you look at the unit circle, where does cos equal 1? So cos is 2pi at 1 and sine is pi/2 at 1

39. Brittni0605

cos equals one at 0 and 2pi

40. babydoll332

then somehow he got 4/p

41. Brittni0605

dont write anything, just read what i write

42. babydoll332

okkkk

43. Brittni0605

|dw:1352672770099:dw|

44. babydoll332

sin=1 at pi/2

45. Brittni0605

Shhh..dont write.

46. Brittni0605

|dw:1352672843682:dw|

47. Brittni0605

|dw:1352672885447:dw|

48. Brittni0605

|dw:1352672912951:dw|

49. babydoll332

ohhhhh

50. babydoll332

ok i get it

51. Brittni0605

Ok, r u sure?

52. babydoll332

god ur amazing i would have been here for a few hours

53. babydoll332

yes i ddint multiply them

54. Brittni0605

thanks, do you want me to give another example..so u can see if u get it right?

55. babydoll332

um ya an easy 1 please

56. Brittni0605

OK, gimme a sec

57. Brittni0605

\[ \cot^{-1} (-1)=?\]

58. babydoll332

pi

59. Brittni0605

No.

60. babydoll332

3pi/4

61. Brittni0605

Yes!

62. babydoll332

question is cot always on the 3rd quadrant?

63. Brittni0605

No, the original question you asked, the answer was pi/4 (thats in the 1st quadrant)

64. babydoll332

but thats for cos

65. babydoll332

not cot

66. babydoll332

cos=1st cot=3rd

67. Brittni0605

No, all quadrants apply for any trig identity.

68. babydoll332

oh i know but for those mostly

69. Brittni0605

The answer is still no.

70. babydoll332

ok thanks :)

71. Brittni0605

Np.