Question

sin((17π)/(12)) find the exact value! please!

Answer 1

i think it is sqrt 6 - sqrt 2 / 4

Answer 2

do you have a calculator?

Answer 3

no...

Answer 4

that's ok, you can use google as a calculator

so if you type "sin(17pi/12)" without quotes into google, you would get this

http://www.google.com/search?hl=&q=sin%2817pi%2F12%29&sourceid=navclient-ff&rlz=1B3GGLL_enUS420US420&ie=UTF-8

Answer 5

ok?

Answer 6

now you type your supposed answer "(sqrt(6)-sqrt(2))/4" without quotes into google to get

http://www.google.com/search?hl=&q=%28sqrt%286%29-sqrt%282%29%29%2F4&sourceid=navclient-ff&rlz=1B3GGLL_enUS420US420&ie=UTF-8


Now IF the two answers are the same, then the two expressions are equal to each other

Answer 7

So let's say hypothetically that sin(17pi/12) gives a result of 0.5 (it doesn't, but let's say it does)

IF (sqrt(6)-sqrt(2))/4 also gave a result of 0.5 (it doesn't, but again let's say it does), then we could say that


sin(17pi/12) = (sqrt(6)-sqrt(2))/4


so this is how you can check any possible answers you get

Answer 8

Or you could use identities? :D

Answer 9

so according to the first link I gave you, what is sin(17pi/12)

Answer 10

true, that's probably the better way to do it

Answer 11

-0.9659

Answer 12

now look at the second link, and tell me what the value of (sqrt(6)-sqrt(2))/4 is

Answer 13

\[\Large \frac{17\pi}{12}= \frac{7\pi}{6}+ \frac{\pi}4\]
(not related to @jim_thompson5910 's checking method, strictly speaking, but may be useful later on)

Answer 14

it didnt work!

Answer 15

look at the second link, what is the value of (sqrt(6)-sqrt(2))/4

Answer 16

you didnt post a second link!

Answer 17

yes I did, but it's ok, I'll do it again

http://www.google.com/search?hl=&q=%28sqrt%286%29-sqrt%282%29%29%2F4&sourceid=navclient-ff&rlz=1B3GGLL_enUS420US420&ie=UTF-8

Answer 18

no they didnt match.

Answer 19

so that proves that sin(17pi/12) = (sqrt(6)-sqrt(2))/4 is false

Answer 20

so use the identity terenzreignz posted and use other trig identities to simplify and try again

Answer 21

ok sqrt 6 +sqrt 2 / 4?

Answer 22

type that into google and tell me what you get

Answer 23

/smh/
If you still care for it, here's the identity you need...
\[\Large \sin(\color{red}\alpha+\color{blue}\beta) = \sin(\color{red}\alpha)\cos(\color{blue}\beta) + \cos(\color{red}\alpha) \sin (\color{blue}\beta)\]

Answer 24

i think 2.80 can you confirm that?

Answer 25

that's incorrect, you typed in (sqrt(6)+sqrt(2))/4 right?

Answer 26

and yes, you should use the latest identity terenzreignz posted

from there, use the unit circle to evaluate

Answer 27

the / is divide right?

Answer 28

yes

Answer 29

1/2 means 1 divided by 2

Answer 30

none of my answers match..

Answer 31

btw, you have to enclose sqrt(6)+sqrt(2) in a set of parenthesis to make sure you divide all of sqrt(6)+sqrt(2) by 4

Answer 32

sqrt(6)+sqrt(2)/4 is NOT the same as (sqrt(6)+sqrt(2))/4

Answer 33

this is helping im more lost now then i was before!

Answer 34

is is -sqrt6 - sqrt2 /4

Answer 35

Guessing when given a multiple choice question may be tempting, but it is ill-advised.

Please try to use the identities ~

Answer 36

look i dont understand the identites you havnt helped me at all!

Answer 37

here's a more simpler example

if I said 1/2 = 2/4 were true, then we would have to show that 1/2 and 2/4 equal the same number

since 1/2 turns into 0.5 and 2/4 turns into 0.5 as well (use a calculator), this means that

1/2 = 0.5
2/4 = 0.5

this proves that 1/2 = 2/4 is true

Answer 38

see how this logic works out?

Answer 39

yes but i put all my quetions into the calculator and none of them came up! this is timed too!

Answer 40

You want the answer?

Answer 41

oh so a test?

Answer 42

sry can't help you there

Answer 43

no a review.

Answer 44

but ive had the page open too long.

Answer 45

Well, you answered MY question correctly, at least.
Use the identity. It was posted, just a few posts ago....

and take
\[\large \color{red}\alpha = \frac{7\pi}{6}\]
and
\[\large \color{blue}\beta = \frac{\pi}{4}\]

Answer 46

ok I'm glad the concept of what I'm explaining makes sense

that's a start

the thing that's probably going wrong is that you're probably entering the expressions incorrectly

you are NOT typing this in sqrt(6)+sqrt(2)/4 since you SHOULD be typing this in (sqrt(6)+sqrt(2))/4

the difference is that set of parenthesis that changes everything

Answer 47

i did that!

Answer 48

(sqrt(6)+sqrt(2))/4 says to divide all of sqrt(6)+sqrt(2) by 4

sqrt(6)+sqrt(2)/4 says to just divide sqrt(2) by 4

Answer 49

hmm what could be going wrong then...

Answer 50

ok i really think its sqrt 2 - sqrt 6 / 4

Answer 51

oh and sqrt 2 should be sqrt(2)

same for sqrt 6

Answer 52

not sure why the parenthesis aren't making it

Answer 53

can you check it since you seem to know how to use it!

Answer 54

but check that with a calculator and tell me what you get

Answer 55

well I want you show you how to use it so you can check other problems on your own

when you get a possible solution, you need to know how to check it with a caclulator

Answer 56

calculator*

Answer 57

that thing doenst work ill never useit again .

Answer 58

can you just tell me if thats right please

Answer 59

You have to use something, though. I still recommend using identities, the old fashioned way of doing things.

Answer 60

@terenzreignz GO AWAY!

Answer 61

it works, I just wish I knew what you were typing in (exactly) so I can pinpoint where things are going wrong

Answer 62

ugh your hellpless both of you

Answer 63

You need to be a bit more diplomatic than that.

Answer 64

fine, be rude