sin (x) = 1/(root 3) .. =0.62. WHAT?

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Tabbris
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#1
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#1
Hello, hey.

I was just wonderign how that was possible. 1/(root 3) is not in the special triangles, the inverse on calculators give 35.26... there are a lot of questions like this, perhaps you could shed some light on this one for me.

THANKS


btw, the question is . Find a solution,where 0 < x < pi/2 (90?)
Do not use a calculator if the answer ccan be found from special triangles.


Also, 0< tita < 2pi
cos tita = -1/3
tita = 1.9, 4.4
where are these decimals coming from?
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raheem94
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#2
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#2
(Original post by Tabbris)
Hello, hey.

I was just wonderign how that was possible. 1/(root 3) is not in the special triangles, the inverse on calculators give 35.26... there are a lot of questions like this, perhaps you could shed some light on this one for me.

THANKS


btw, the question is . Find a solution,where 0 < x < pi/2 (90?)
Do not use a calculator if the answer ccan be found from special triangles.


Also, 0< tita < 2pi
cos tita = -1/3
tita = 1.9, 4.4
where are these decimals coming from?
 \theta is called 'theta' not 'tita'.

You haven't given the complete question,  0 &lt; x &lt; \dfrac{\pi}2 is just the range, where is the equation for which we need to find the solutions?
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Intriguing Alias
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#3
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#3
(Original post by Tabbris)
Hello, hey.

I was just wonderign how that was possible. 1/(root 3) is not in the special triangles, the inverse on calculators give 35.26... there are a lot of questions like this, perhaps you could shed some light on this one for me.

THANKS


btw, the question is . Find a solution,where 0 < x < pi/2 (90?)
Do not use a calculator if the answer ccan be found from special triangles.


Also, 0< tita < 2pi
cos tita = -1/3
tita = 1.9, 4.4
where are these decimals coming from?
For \dfrac{1}{\sqrt{3}}, draw an equilateral triangle of side length 2. Then 'chop' it in half from any corner to the middle of the opposite side. Proceed to work out sides and angles and how they relate.

For the second thing, I've got to start by saying it's theta, not tita.

And I'm pretty certain they're using a calculator there. What's wrong with decimals?
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electriic_ink
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#4
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#4
(Original post by hassi94)
For \dfrac{1}{\sqrt{3}}, draw an equilateral triangle of side length 2. Then 'chop' it in half from any corner to the middle of the opposite side. Proceed to work out sides and angles and how they relate.
That doesn't help with sin theta = 1/sqrt(3).
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raheem94
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#5
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#5
(Original post by hassi94)
For \dfrac{1}{\sqrt{3}}, draw an equilateral triangle of side length 2. Then 'chop' it in half from any corner to the middle of the opposite side. Proceed to work out sides and angles and how they relate.

For the second thing, I've got to start by saying it's theta, not tita.

And I'm pretty certain they're using a calculator there. What's wrong with decimals?
The OP's first post isn't clear, she needs to write the complete question.
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Intriguing Alias
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#6
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#6
(Original post by electriic_ink)
That doesn't help with sin theta = 1/sqrt(3).
Oh sorry I didn't actually read the title while I was writing that, just the actual post where sine wasn't mentioned

Yeah then OP, use a calculator.
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Intriguing Alias
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#7
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(Original post by raheem94)
The OP's first post isn't clear, she needs to write the complete question.
Indeed, it's a pretty confusing post.
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Tabbris
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#8
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(Original post by raheem94)
 \theta is called 'theta' not 'tita'.

You haven't given the complete question,  0 &lt; x &lt; \dfrac{\pi}2 is just the range, where is the equation for which we need to find the solutions?
the equation is this :

sinx x = 1/(root 3)


(i don't know how to do the square root sign but it's a fraction under one)

Sorry about the theta >< I've never seen it written down before , but now I have
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Tabbris
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#9
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(Original post by hassi94)
For \dfrac{1}{\sqrt{3}}, draw an equilateral triangle of side length 2. Then 'chop' it in half from any corner to the middle of the opposite side. Proceed to work out sides and angles and how they relate.

For the second thing, I've got to start by saying it's theta, not tita.

And I'm pretty certain they're using a calculator there. What's wrong with decimals?
I've tried to do that earlier, but I can't seem to make it work with the triangles.

nothing is wrong with decimals. I just don't understand how to get it as my answer
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raheem94
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#10
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#10
(Original post by Tabbris)
the equation is this :

sinx x = 1/(root 3)


(i don't know how to do the square root sign but it's a fraction under one)

Sorry about the theta >< I've never seen it written down before , but now I have
You will probably need to use a calc for this question. Does the question gives any more information?

If you haven't seen any word written before, then its always better to first google it and check the spelling of it, don't mind it btw.
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raheem94
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#11
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(Original post by Tabbris)
the equation is this :

sinx x = 1/(root 3)


(i don't know how to do the square root sign but it's a fraction under one)

Sorry about the theta >< I've never seen it written down before , but now I have
By the way, are you sure the question asks you to find the value of  x \ ?

It may be asking you to find  cosx \  or \ tanx
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Tabbris
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#12
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(Original post by hassi94)
Oh sorry I didn't actually read the title while I was writing that, just the actual post where sine wasn't mentioned

Yeah then OP, use a calculator.
but what do I type into the calculator? o.o

inverse sine gives me 35.5 something...normal sin gives me 0.01007...

How does that eventually work out to be solved as 0.62?
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raheem94
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#13
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#13
(Original post by Tabbris)
but what do I type into the calculator? o.o

inverse sine gives me 35.5 something...normal sin gives me 0.01007...

How does that eventually work out to be solved as 0.62?
You need to use the inverse sin.

If your calc is in degrees then you will get 35deg. if it is radian then you will get 0.62rad.
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Intriguing Alias
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#14
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#14
(Original post by Tabbris)
I've tried to do that earlier, but I can't seem to make it work with the triangles.

nothing is wrong with decimals. I just don't understand how to get it as my answer
For sin(x) it won't work, sorry that was my mistake of not reading properly.

Type sin^{-1}\left(\dfrac{1}{\sqrt{3}} \right) into your calculator and that will give you the principle value. Do you then know how to find the other values (if there are any others in the range asked)?


Oh I see... You need to set your calculator into Radians mode - it's currently outputting degrees.
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Tabbris
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#15
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#15
(Original post by raheem94)
By the way, are you sure the question asks you to find the value of  x \ ?

It may be asking you to find  cosx \  or \ tanx

There is no more information from the question. and I do not think so. this is part e) of the question. part a) was sin x =1/2 and the answer for that was pi/6 which i understand and used the special triangle for it.

I'm not sure how i can use the calculator to get 0.62

thanks
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raheem94
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#16
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#16
(Original post by Tabbris)
There is no more information from the question. and I do not think so. this is part e) of the question. part a) was sin x =1/2 and the answer for that was pi/6 which i understand and used the special triangle for it.

I'm not sure how i can use the calculator to get 0.62

thanks
Configure your calc to give the answer in radian.

As the range, 0 &lt; x &lt; \dfrac{\pi}2 , is given in radians hence we need to give the final answer in radian.

Once you have changed the configuration to radians, then just do,  sin^{-1}\left(\dfrac{1}{\sqrt{3}} \right)
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StudyAk
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#17
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#17
(Original post by Tabbris)
Hello, hey.

I was just wonderign how that was possible. 1/(root 3) is not in the special triangles, the inverse on calculators give 35.26... there are a lot of questions like this, perhaps you could shed some light on this one for me.

THANKS


btw, the question is . Find a solution,where 0 < x < pi/2 (90?)
Do not use a calculator if the answer ccan be found from special triangles.


Also, 0< tita < 2pi
cos tita = -1/3
tita = 1.9, 4.4
where are these decimals coming from?
Just because 1 over root 3 is involved in the question doesn't mean it in going to be a non calculator thing.

If you read the question carefully it is asking you for where solutions 0 < x < pi/2
So you can work it out in degree like you have done which came out to 35.26 right? HOWEVER it says it has to be in radians hence pi/2. To convert degrees in radians you have to mulitply 35.26 by PI (3.14....) then divide by 180.

So 35.26 x Pi / 180 = Answer you were looking for
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raheem94
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#18
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#18
(Original post by Tabbris)
There is no more information from the question. and I do not think so. this is part e) of the question. part a) was sin x =1/2 and the answer for that was pi/6 which i understand and used the special triangle for it.

I'm not sure how i can use the calculator to get 0.62

thanks
Do you know how to change the configuration to radians in your calc?
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Tabbris
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#19
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#19
(Original post by raheem94)
You need to use the inverse sin.

If your calc is in degrees then you will get 35deg. if it is radian then you will get 0.62rad.
whoa, I think that is it >< I didn't realise about the calculator mode thing o.o

Thanks!

Whoa >, I can't believe all this effort was just because I didn't have the right mode :/
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Tabbris
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#20
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#20
(Original post by StudyAk)
Just because 1 over root 3 is involved in the question doesn't mean it in going to be a non calculator thing.

If you read the question carefully it is asking you for where solutions 0 < x < pi/2
So you can work it out in degree like you have done which came out to 35.26 right? HOWEVER it says it has to be in radians hence pi/2. To convert degrees in radians you have to mulitply 35.26 by PI (3.14....) then divide by 180.

So 35.26 x Pi / 180 = Answer you were looking for
Ack >,< THANK YOU DO MUCH!
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