Ceiling Function/Examples/Ceiling of Root 2
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Theorem
- $\ceiling {\sqrt 2} = 2$
where $\ceiling x$ denotes the ceiling of $x$.
Proof
The decimal expansion of $\sqrt 2$ is:
- $\sqrt 2 \approx 1.41421 \ 35623 \ 73095 \ 0488 \ldots$
Thus:
- $1 < \sqrt 2 \le 2$
Hence $2$ is the ceiling of $\sqrt 2$ by definition.
$\blacksquare$
Sources
- 1997: Donald E. Knuth: The Art of Computer Programming: Volume 1: Fundamental Algorithms (3rd ed.) ... (previous) ... (next): $\S 1.2.4$: Integer Functions and Elementary Number Theory