karatechopper one year ago Can someone please check a trig function worksheet for me? I'm practicing! :)

1. lfreeman1285

I might be able to help!

2. karatechopper

Thanks! @IFreeman1285

3. Nnesha
4. Loser66

WWWWWWWWWWWWWooooooooooooooooah!! you memorize all of them??? A/MA/Zing

5. karatechopper

Didn't memorize! I use the hand method. :)

6. Loser66

7. lfreeman1285

memorizing them isn't incredibly difficult, I had to for precalculus. These look correct! I didn't find any mistakes in my quick glance. I'll continue looking though.

8. karatechopper

So basically each finger on the hand has a different angle. Thumb-90 Index-60 Middle-45 Ring-30 Thumb-0 The palm is always 2. On top= cosine (side where the thumb points up) On bottom=sine (side where the pinky finger is) Say for example we are given the problem find Cos(pi/6) We know that pi/6 is a 30 degree angle, thus we put our ring finger down. We also can tell from the unit circle that when cos is pi/6, cos is positive. We put our ring finger down and then see that we have up on the cosine side above the folded finger. We have 3 fingers (ON TOP-COSINE) Now, anytime we look at the fingers, we need to square root them. So we say sqrt of 3, and then we put the value above the 2 in the palm bc this isn't Tangent or Cotangent where we have to look at both Sine and Cosine. Therefore, the answer for cos(pi/6) is sqrt3/2. Make sense? :)

9. karatechopper

Thank you free man! Yeah this is a precalc review for a calc quiz I'm taking tomorrow haha.

10. karatechopper

@Loser66 there's an explanation example for the hand method I use.

11. Loser66

Thank you.

12. lfreeman1285

it looks like you're going to do well on that quiz then haha

13. karatechopper

I would hope so! Are they all correct? The quiz tomorrow is timed and I have a lot of other tests/discussions, and work in school tomorrow. I hope I'm not worn out by the time I get to this quiz! :) .

14. Nnesha

tan 120 is it -sqrt{3} or positive ?

15. lfreeman1285

It's negative, because its in the second quadrant.

16. Nnesha

http://prntscr.com/8at9tn looks like square root tan isn't positive in 2nd q

17. Nnesha

no i mean on the worksheet :) there is just sqrt{3}

18. lfreeman1285

Tangents are negative in the second and fourth. Cosines are negative in the second and third. Sines are negative in the third and fourth.

19. lfreeman1285

So just being careful about which quadrant everything is in should help. Drawing the circle at the top of the test is what helped me.

20. Nnesha

yes i know.

21. Nnesha

that question was for kara :D

22. karatechopper

Thanks!!!

23. karatechopper

Help a lot guys!

24. karatechopper

Have a good day/night everyone! :) x

25. Nnesha

csc =1/sin so$\huge\rm csc(\frac{ 7\pi }{ 6 })=\frac{ 1 }{ \frac{ -1 }{ 2 } }$

26. karatechopper

-2!

27. Nnesha

yes there is -1/2 on the wrkshet

28. karatechopper

Lol yeah I just saw that haha. Fixed, thank you! :) x

29. Nnesha

11) sec 180 is wrong there is no way you can get 1 for sec tan can be one

30. Nnesha

good job :) 3 mistakes i guess typoz :D tan 120 sec 180 csc (7pi/6) :=)