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#1 2017-11-06 04:06:08

numquester
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Registered: 2016-12-12
Posts: 15

Geogebra: Why does sin() give the wrong value?

To present this as simply as possible, say I have a right triangle with sides: adjacent = 0.71; opposite = 0.71; hypotenuse = 1. The angle theta is 45 degrees. When I enter in the input box, sin(45) , I get 0.85, which is obviously not the sine of 45 degrees.

Am I doing something wrong here?  In case it is relevant, I am using Geogebra 5 with the angle unit set to degrees.

Last edited by numquester (2017-11-06 04:08:37)

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#2 2017-11-06 04:56:10

numquester
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Registered: 2016-12-12
Posts: 15

Re: Geogebra: Why does sin() give the wrong value?

Answered by a member at  the Geogebra forum.  Degrees must be indicated within the function.  The angle unit setting in Geogebra's preferences is for the display of graphics only; not for setting input value units of those functions which expect angle values as the input, such as sin(), cos(), tan().

The degree symbol must be entered following the degree number.  A popup window with symbols can be brought up by clicking the button in the far left of the input box, where the degree symbol can be found at the bottom of the window (in Geogebra 5).

I think my point of confusion stemmed from the angle unit setting.  When setting the angle unit in a calculator, any functions which expect angle values will use that angle unit setting, where in Geogebra, only graphing is affected by the angle unit setting.  Also in Geogebra, there is nothing in the preferences window stating that the angle unit setting only affects graphing.

Last edited by numquester (2017-11-06 05:12:17)

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#3 2017-12-10 02:20:19

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,843
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Re: Geogebra: Why does sin() give the wrong value?

Actually, you can open settings and set Angle Units to Degree, if you want to.


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#4 2017-12-15 11:58:32

zetafunc
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Registered: 2014-05-21
Posts: 2,154
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Re: Geogebra: Why does sin() give the wrong value?

A shortcut for the degree symbol in GeoGebra is also Alt + O, which you can enter as part of your input.

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