how to get answers in terms of pi on a calculator

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emiuk
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im doing radians and my calculator is still in the radians mode but all the answers are coming up as decimals and I cant change them to pi. anyone have any ideas what I could do? I have a casio fx-83gt plus if that helps.

thanks !!
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Cov3rt
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Change it to degrees
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emiuk
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but I need the answer in radians in terms of pi
(Original post by Cov3rt)
Change it to degrees
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RDKGames
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(Original post by emiuk)
but I need the answer in radians in terms of pi
How are you obtaining the radians on your calculator??

Some fairly simple rational coefficients of \pi can be obtained and shown; i.e. \dfrac{7\pi}{2} + \dfrac{4\pi}{3} = \dfrac{29\pi}{6}

but others might be too much for a calculator; i.e. \dfrac{11\pi}{59} + \dfrac{28\pi}{13} = 7.35222.... But this is not that much of a problem. Just ignore pi and do "11/59 + 28/13" first and that will give you the fraction. Then include pi alongside it, job done.


Also when doing something like inverse cosine of a number, you're not always going to get a multiple of pi for your calculator to show, so don't expect it every time.
Last edited by RDKGames; 1 year ago
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emiuk
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I'm getting the radians because it's in the radians mode. Thanks for this, but I was more specifically looking to see if there was another mode I could change it to since this one for some reason suddenly stopped working (for example tan-1(45) will come up as 1.54857.... instead of pi/2 as it used to)
(Original post by RDKGames)
How are you obtaining the radians on your calculator??

Some fairly simple rational coefficients of \pi can be obtained and shown; i.e. \dfrac{7\pi}{2} + \dfrac{4\pi}{3} = \dfrac{29\pi}{6}

but others might be too much for a calculator; i.e. \dfrac{11\pi}{59} + \dfrac{28\pi}{13} = 7.35222.... But this is not that much of a problem. Just ignore pi and do "11/59 + 28/13" first and that will give you the fraction. Then include pi alongside it, job done.


Also when doing something like inverse cosine of a number, you're not always going to get a multiple of pi for your calculator to show, so don't expect it every time.
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the bear
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just divide the answer by pi. if you get 0.3 then the answer was 0.3pi
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RDKGames
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(Original post by emiuk)
I'm getting the radians because it's in the radians mode. Thanks for this, but I was more specifically looking to see if there was another mode I could change it to since this one for some reason suddenly stopped working (for example tan-1(45) will come up as 1.54857.... instead of pi/2 as it used to)
But \arctan(45) is not \dfrac{\pi}{2}. Why would it come up as that?
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emiuk
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in radians it is
(Original post by RDKGames)
But \arctan(45) is not \dfrac{\pi}{2}. Why would it come up as that?
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RDKGames
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(Original post by emiuk)
in radians it is
But it's not...

The answer is something 'close' to pi/2, but it's not exactly pi/2
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emiuk
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thanks !!
(Original post by the bear)
just divide the answer by pi. if you get 0.3 then the answer was 0.3pi
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emiuk
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ok but for the questions on my exam when it asks to find an angle giving the the answer in pi i need the pi form
(Original post by RDKGames)
But it's not...

The answer is something 'close' to pi/2, but it's not exactly pi/2
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Strelzo
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(Original post by emiuk)
I'm getting the radians because it's in the radians mode. Thanks for this, but I was more specifically looking to see if there was another mode I could change it to since this one for some reason suddenly stopped working (for example tan-1(45) will come up as 1.54857.... instead of pi/2 as it used to)
Try resetting your calculator completely:

*shift, 9, 3, =, AC*

and then change back to the radians mode via your setup, if there is any problem, this should hopefully fix it if it is displaying unexpected results.
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RDKGames
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(Original post by emiuk)
ok but for the questions on my exam when it asks to find an angle giving the the answer in pi i need the pi form
Then those angles will be simple ones, definitely not something where you need to know or write arctan(45).
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emiuk
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yeah I tried it but it didn't work
(Original post by Strelzo)
Try resetting your calculator completely:

*shift, 9, 3, =, AC*

and then change back to the radians mode via your setup, if there is any problem, this should hopefully fix it if it is displaying unexpected results.
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Strelzo
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(Original post by emiuk)
yeah I tried it but it didn't work
Hmm, perhaps look online to see if there's another solution to your problem?I thought for sure that'd work, as it works for me whenever I have a calculator problem.
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the bear
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(Original post by RDKGames)
Then those angles will be simple ones, definitely not something where you need to know or write arctan(45).
i expect that the original problem involved arctan(1)
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emiuk
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but I do need it.... for example a question is:
solve the equation of cot^2 x + cosec^2 x=7 giving all the solutions in the interval 0 ≤ x ≤ 2pi in terms of pi

and that comes to √1/3 =tanx I have worked out so far...

(Original post by RDKGames)
Then those angles will be simple ones, definitely not something where you need to know or write arctan(45).
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emiuk
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ive been looking for the past half an hour but found nothing useful :/
this happened to me with a different calculator a few days ago as well and after an hour or so it went back to showing pi. it's really reassuring to go into an exam knowing my calculator could f me over
(Original post by Strelzo)
Hmm, perhaps look online to see if there's another solution to your problem?I thought for sure that'd work, as it works for me whenever I have a calculator problem.
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RDKGames
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a) It does not reduce to \dfrac{1}{\sqrt{3}} = \tan x entirely.

b) Still not sure where you are pulling arctan(45) from, unless I'm misinterpreting what you're trying to say.
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emiuk
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1) I used decimals to see if I was going in the right direction using 1/√3= tan x and I got all the angles right (I checked by converting the answer into decimals). I did this to check that I was doing the right method, but I still cant get the answers in pi form

2) it was just an example because it's what I used for one of the last ones where my calculator showed the answer in pi

(Original post by RDKGames)
a) It does not reduce to \dfrac{1}{\sqrt{3}} = \tan x entirely.

b) Still not sure where you are pulling arctan(45) from, unless I'm misinterpreting what you're trying to say.
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