The Montgomery–Taylor constant is less than 1.3275 #
The single numerical input to both headline bounds. Since (1/√2)² = 1/2 exactly, the values
cos(1/√2) and √2 sin(1/√2) are alternating series with rational terms, so bounding them needs
no estimate at an irrational argument: five terms bound the first from above, four bound the second
from below, and the gap to 1.3275 is about 7 · 10⁻⁷.
The numerical input. C_MT < 1.3275, which is exactly what both headline bounds need:
2 - 1.3275 = 0.6725 and 3/2 - 1.3275/2 = 0.83625.
C₀ = 2 - C_MT.
C₁ = 3/2 - C_MT/2.