Teensy 3.0

Nantonos:

cyclegadget:
Rather impressive difference!

  //time elasped = 29721 micros = teensy

//time elasped = 47436 micros = Uno




Is it?

I had the same reflection. But looking at the code I think we are comparing apples with pears.
I see that sin is defined as

extern double sin(double __x) __ATTR_CONST__;

and double is not a fixed in bytes according to Double-precision floating-point format - Wikipedia
I'm not sure how to fix this but If you would print the result of sin(1.2) with teensy 3 and uno I expect to get different numbers.
Best regards
Jantje