## NY,NY one year ago Which trigonometric expression does not simplify to 1? (see link)

1. NY,NY
2. Vocaloid

well, let's try each answer one by one and see what we get, shall we?

3. NY,NY

ok.

4. Vocaloid

|dw:1434685599699:dw|

5. anonymous

help me please my question is at the top of the feed

6. Vocaloid

does that make sense?

7. NY,NY

I dont understand how cos^2/sin^2 became just cos^2.

8. Vocaloid

I distributed sin^2(x)

9. Vocaloid

|dw:1434685846593:dw|

10. Vocaloid

see how sin^2(x) cancels out?

11. Vocaloid

|dw:1434685945486:dw|

12. Vocaloid

|dw:1434685962311:dw|

13. NY,NY

Oh yes that makes more sense.

14. NY,NY

Thank you for explaining that.

15. Vocaloid

ok, so we know that #1 is not the right answer because we get 1 in the end

16. Vocaloid

let's move on to number 2

17. NY,NY

Ok.

18. Vocaloid

|dw:1434686053840:dw|

19. Vocaloid

|dw:1434686204867:dw|

20. Vocaloid

does this make sense so far?

21. NY,NY

yes, because you used the Pythagorean identity at the end, right?

22. Vocaloid

yup! ok, we know that #2 is out, because we ended up with 1, so let's move on to #3

23. NY,NY

Right.

24. Vocaloid

|dw:1434686335785:dw|

25. Vocaloid

now, I believe #3 is the right answer, but let's check #4 just in case

26. Vocaloid

|dw:1434686426089:dw|

27. Vocaloid

|dw:1434686523673:dw|

28. Vocaloid

whew, that took a while, but do you understand everything so far? :)

29. Vocaloid

the important thing to remember, is that when you have csc, sec, cot, or tan, you can re-write them in terms of cos or sin, which usually helps you cross things out and simplify :)

30. NY,NY

Im a little confused with the second step you took.

31. Vocaloid

which one? #3 or #4?

32. NY,NY

#4.

33. Vocaloid

can you tell me exactly which part is confusing?

34. NY,NY

the step that the arrow is pointing to |dw:1434687552340:dw|

35. NY,NY

Im confused how that concluded from the previous step, where you substituted the reciprocals.

36. Vocaloid

|dw:1434687726888:dw|

37. Vocaloid

which leaves me with|dw:1434687748727:dw|

38. Vocaloid

does it make it more clear? or is there something you're still unsure about?

39. NY,NY

Ok, yes that makes sense.

40. NY,NY

So that leaves us with choice 3.

41. Vocaloid

yup ~

42. NY,NY

Ok, thank you for helping.