Trig function values (Sin 180 , Cos 90 etc) not exactly 0

[Virdinetics]

Hello forum,

I am using sin 180, sin 360, cos 90, cos 270 etc in one of my apps. These should be 0, but I get numbers like 1.7949E-9 etc.

I appreciate that this is close to 0, but due to this discrepancy I am getting errors in my app.

Is there a solution for this problem in the back end ?

Thanks,

Virdinetics

[TimAI2]

Like so ?

Use the absolute block to remove the minus sign

[Virdinetics]

Yes there are several ways to get rid of the problem by programming. But I guess the basic primitive should give the correct answers. Or at least update the documentation to say that these items will not give exact values and the users are aware of the error. 

So my question is if the developers could look into the problem in the back-end programming rectify the problem there ?

Cheers

[SteveJG]

There is no problem   App Inventor and Android use FloatingPoint Math ....0.0000001 for all practical purposes is zero.  App Inventor uses the Android Math libraries. 

Regards,

Steve

[Evan Patton]

It seems reasonable to add these as special test cases. The issue here is that our blocks use degrees but the underlying methods use radians. We internally convert from degrees to radians, but doing so introduces a small amount of error due to the inclusion of pi in the computation. Since these are common enough cases it seems like we should be able to do this.

Regards,

Evan