Hello
This is because the Android Calculator on all android phones uses Radians instead of Degrees thus it gives inaccurate answers because you expect answers according to degrees.
You could first convert the degree (e.g. 37) into radian by using (pi/180)*degree value.
Or you could use Holo Calculator or Real Calc which lets you set the mode b/w Degrees and Radians.
-Deepansh
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