0218132人目の素数さん
2021/03/24(水) 13:54:30.48ID:IfA1byk6(略証)
1 = π/3 - δ,
δ = 0.04719755
加法公式で
tan(1) = tan(π/3 - δ)
= {tan(π/3) - tanδ}/{1 + tan(π/3)tanδ}
= (√3 - tanδ)/{1 + (√3)tanδ}
< 3/(√3 + 4 tanδ)
< 3/(√3 + 4 δ)
< 3/(1.732 + 4・0.047)
= 3 / 1.92
= (5/4)^2
< π/2,
なお tan(π/4) = 1,