Geometry Level 5

If the value of the given expression is a, then what is $$\lfloor a \rfloor$$?

Details And Assumptions:

1. $$x,y$$ are cartesian plane co-ordinates.

2. Expression given here is a real-valued one, not complex-valued.

3. $$sin^{-1}x,cos^{-1}x$$ are defined on $$[-1,1]$$

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