Question

sin(arcsin(-11π/13)

I'd really just like an explanation of this one.

Answer 1

I don't know why I'm forgetting how to do this, but it's been awhile and my final is coming up and I want a better understanding of it.

Answer 2

do you know the init Circle?

Answer 3

Yep

Answer 4

when you at look the unit circle what quard would Sin be in?

Answer 5

I see that it goes -11π, so I believe it's going clockwise around the unit circle and I think it gets to Q3.

Answer 6

yes correct, so in the problem what does that tell you?

Answer 7

I don't know...hahaha, rephrase that maybe?

Answer 8

from looking at this problem and taking the information you already have what would you say the answer is? sin(arcsin(-11π/13)

Answer 9

do you understand arcsin and what that means??

Answer 10

crap, I wrote it down wrong. It was arcsin(sin(-11π/13))

Answer 11

I have a pretty good understanding of how to use it. I'm rusty, though.

Answer 12

okay, let us take this and break it down on what you know, you start I will fill in if needed.

Answer 13

I believe sin(ø) = arcsin (-11π/13) in this situation.

Answer 14

you are right, but how did you do that?

Answer 15

I just kind of have that memorized. I guess I never really grasped that...

Answer 16

okay, now I have a stupid what is the question asking for??? I am a little lost with the question here does it ask to solve or what?

Answer 17

Find the exact value of the given expression. Simplify your answer (rationalize the denom)

Answer 18

I also have that the answer is -2π/13

Answer 19

I don't really understand where the 2π comes from.

Answer 20

because recall the unit circle has a total of 360 degrees right?

Answer 21

Yep and 2π is 360º

Answer 22

2/pie is a point on the Unit the circle in which the angle is 360.. you beat to that one good job

Answer 23

So, my picture shows the line -11π/13 and the distance between that line and the 180º line is 2π/13.

Answer 24

Having a hard time understanding why it's 2π and not just π.

Answer 25

Probably just overthinking it.

Answer 26

what I am questioning here the negative here in this case?

Answer 27

because you start with a negative you will most likely end that way..

Answer 28

2pie is at the 360 degrees which has points 0,0 so how can that be a negative result help here?

Answer 29

One sec, gonna post a photo of what is giving me a headache.

Answer 30

I think we are both getting the same headache on this. This problem is going down..

Answer 31

Hahaha, I'm tellin' you. I haven't had any problems with any other questions, but this one is just destroying my brain.

Answer 32

yeah, the same thing only that my brain is dead because I am stuying Vectors myself.

Answer 33

what I am missing here????

Answer 34

is the question still \[\sin (arcsin (-11 \pi/3)\]

Answer 35

arcsin(sin(-11π/3))

Answer 36

yes sir, please help me I am getting a major headache here

Answer 37

Messed up the on the original post

Answer 38

here's a hint..

arcsin( sin x) = x

sin (arcsin x) = x

cos( arc cos x) = x

arc cos (cos x) = x

tan (arctan x) = x

arctan (tan x) = x

does that help?

Answer 39

There is the picture that I was trying to describe.

Answer 40

I wish that helped, but I still can't figure out why it is -2π/13

Answer 41

is that included in the question? or is that your solytion?

Answer 42

Solution. It's an answer key and I'm trying to decipher it.

Answer 43

I know it is -2π/13 because of the range, but I don't know where the 2π came from.

Answer 44

use the hint i gave you...here's a demo \[\sin (\sin^{-1} ( \frac{\pi}{2} ) ) = \frac{\pi}{2}\]
\[\sin^{-1} (\sin ( \frac{2 \pi}{5} ) ) = \frac{2 \pi}{5}\]
getting it now?

Answer 45

\[\sin^{-1} (\sin ( \frac{-11\pi}{3} ) ) = -\frac{11\pi}{3}\]
then simplify that you get \[-\frac{2\pi}{3}\]
make sense?

Answer 46

lgbasallote what did I miss here? I mean I thought for sure I was going the right way what did I do in my steps that went wrong here? Help me to understand..

Answer 47

How'd you simplify to that?

Answer 48

i think i wrote the wrong thingies lol...

Answer 49

but that's the concept

Answer 50

Yeah, I knew what you were saying with the others. It's this deal here. I don't understand how it is simplifying from 11π to 2π.

Answer 51

It's like it just magically disappears.

Answer 52

reference angles

Answer 53

Heh, I feel dumb for not knowing still.

Answer 54

Mrcarey I am so sorry I took the long way here.

Answer 55

Haha, no problem at all. I've been at it for so long, it didn't even feel that long.

Answer 56

ha ha yeah better next time right? HA HA..

Answer 57

Exactly! Thanks for trying at least. Good luck with the vector calc. I'll be THERE soon enough.

Answer 58

I am Physics Engineering major myelf

Answer 59

Mech E. for me. Math math math math and more math!

Answer 60

you got this now

Answer 61

Yeah, I feel better about it. Got one more day of review in class, so I'll probably bring it up with him anyway. Thanks again!

Answer 62

do you another problem you need help on? Just asking here

Answer 63

Nope, this one seemed to be the only one I kept coming back to. This stupid thing made everything else seem easy!

Answer 64

yeah, I only hope for me it is just one problem that will allow everything to be easy after that. Fat chance ha ha

Answer 65

Hahahaha, no way. I've peeked at that stuff and needed to take a nap after.

Answer 66

did that one already.. I took a 5hrs nap

Answer 67

I am doing Calc1 andPhysics 1 with Calc

Answer 68

I'll be doing that in the Fall. Well, no Physics yet, couldn't get in the class. General Chem 1 and Calc 1. Gonna be exciting.

Answer 69

what school?

Answer 70

Doing community for now, so I can transfer to University of Washington Seattle.

Answer 71

You?

Answer 72

cool I live Iin Portland Ore myself..

Answer 73

I will start Sept 24th at Jr College than transfer to Tarleton ST university in TX in Spring 2013

Answer 74

Awesome, TX should be pretty fun. Definitely a change of scenery.

Answer 75

I am studying math and Physics by watching videos and taking notes on my own

Answer 76

Khan Academy?

Answer 77

yeah StephenVille is very small town though

Answer 78

who is Khan A?

Answer 79

www.khanacademy.com

MIT grad who made his own site that teaches every kind of math and most sciences.

Answer 80

Free site for learning. I've used it for awhile now. Especially when I get bad professors.

Answer 81

funny you just posted MIT, Because I am using thier open courses on line for the video in math and Physics

Answer 82

Haha, that works, too! You'd probably like his teaching style. He is very helpful and has tons of videos. I always recommend the site.

Answer 83

thanks will check it out, hey you have a great night and if you need me to help me message me

Answer 84

you

Answer 85

Sounds like a plan! Have a good night!

Answer 86

you too.