Calculator that miscalculates???

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houdini195 Posted messages 9 Status Membre -  
 Hanna2006 -
Hello everyone, I'm posting this message because I'm completely stunned and shocked. I just bought a Casio Graph 90+E calculator and tried it for an exercise that couldn't be simpler, and while I'm typing 3 * sin (25), the result displayed is -0.3970552503, a result that makes no sense in relation to my exercise (calculating a side of a triangle). Intrigued, I took my old college calculator, the Casio fx-92, which shows me 1.267854785!!!! At that moment, my brain starts to sway, and I type the same calculation with my phone calculator, which gives me the same result as the high school calculator... Finally, with a friend's high school calculator, an older Casio model 20 or 30 maybe, the result is the one that seems coherent for my exercise, that of the college calculator.
Anyway, it seems to me that the correct result is 1.26... I would still like someone to explain how this happens and how to solve the problem on my recently purchased high school calculator.

Thank you in advance

PS: Two things seem important to point out: first of all, there is a noticeable discrepancy in any calculation involving trigonometry, and secondly, it may be important that my father installed the Python update that was required by the program (I got stuck with an old model from 2017) that morning.

3 réponses

houdini195 Posted messages 9 Status Membre 3
 
I FOUND IT!!! Just for information, if one day someone has the same issue, the problem is the unit of the angle; it needs to be in degrees while mine was in radians... In the Set Up menu to change it, thank you anyway for your participation.
3
Axe
 

Thanks for the info, I had the same problem yesterday!

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Hanna2006
 

Good evening, I have a Casio calculator 2nd edition and I also had calculation issues with the calculator, and actually, it was enough for me to change the angle unit, basically you need to press setup then set it to De9... at least in my case it worked, thanks to that I no longer have calculation problems with your tan and sin... that's for people who have the same calculator as mine and who have also encountered the same problem as me.

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molkinou
 
The true result of 3 * sin(25) is 1.2678547852220983085609354689432.
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houdini
 
How can you explain the bug in my calculator? And especially how to get it working properly again? I repeat myself, but it is all the more intriguing that my phone has the same error...
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georges97 Posted messages 14506 Registration date   Status Contributeur Last intervention   2 897
 
Hello,

I'm not an expert in math, but the problem intrigued me.

On the Windows 10 calculator, if you do:

25 sin * 3, you get the correct result, which is 1.26...

If you do:

3 * sin * 25, you get 3.29..., which is close to your result.

If you do:

3 * 25 sin and then hit enter, you get 1.26...

So it might be a matter of the order of operations.

Best regards.
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houdini195 Posted messages 9 Status Membre 3
 
In reality, the problem is the value of the sine, meaning that my calculator indicates that sin 25 is negative while it is positive. For example, any sine, cosine, or tangent will have an erroneous value: cos(25) = 0.99... according to my calculator, whereas the correct result is 0.90... It seems that the "recording" of the trigonometric values has been done incorrectly, which is totally nonsensical...
Personally, it seems to me that I have tried everything regarding the entry mode of the operators; maybe I should reset my calculator to see?
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