Hi @thunkable , The Math block cos (90 degrees) returns a small number instead of exactly zero. Same for -90 degrees. Also fails in Android version. [image] (Note: The intermediate variable is needed since the “from Label set Text to” block won’t coerce non-text values.) Thanks! BillG

He’s not inputting 1.57, the answer is 0.00000000157 instead of 0. For more on floating point arithmetic see here: http://www.smbc-comics.com/?id=2999 :joy:

I think it is radian, but I checked that in radian cos 90 ≈ 0.44 Just to confirm I ask him to put π/2 ≈ 1.57 If it calculates in radians, then result will tend to 0

It works in degrees, apparently: http://appinventor.mit.edu/explore/ai2/support/blocks/math.html#cos But that was a nice idea for a test.

Android returns 0.99962 for cos(1.57 degrees). What’s the significance of 1.57? I don’t see that in my iOS/Android answers. Thanks! BillG

Oops, missed the updates, you were testing for degrees vs radians. Thanks! BillG

In Android we have this block, maybe ios too have that [https://thunkable.com/explore/ai2/support/blocks/math.html#convertdeg]

π/2 radians is 90 degrees so 1.57 was an approximation for 3.1415…/2 I think it’s safe to say that we’re working in degrees here since cos(0) is 1.

Thunkable uses degrees instead of radians. Thanks! BillG

Yes @BillG , I just checked that https://thunkable.com/explore/ai2/support/blocks/math.html#cos

[Bug] cos (90) doesn't return exactly zero

Questions about Thunkable

BillG June 26, 2017, 12:47am 24

Yes, Thunkable for iOS is presently being beta tested.

Thanks!
BillG

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[Bug] cos (90) doesn't return exactly zero

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