Interface:Tau day theorems 2

This is the second page of theorems one might prove for Tau day. If you find them too hard, there are hints at Help:Tau day theorems 2 hints.

 param (PROPOSITIONAL Interface:Classical_propositional_calculus ) param (FIRSTORDER Interface:First-order_logic_with_quantifiability (PROPOSITIONAL) )

kindbind (object real) var (real x y z θ α)

term (real (+ real real)) term (real (- real)) term (real (− real real)) term (real (· real real)) term (real (/ real real)) term (real (√ real)) term (real (sin real)) term (real (cos real)) term (real (τ)) term (real (0)) term (real (1)) term (real (2)) term (real (4)) term (real (8))

stmt (Sine2  ((sin ((τ) / (2))) = (0))) stmt (CosineNegative4  ((cos (- ((τ) / (4)))) = (0))) stmt (Cosine4  ((cos ((τ) / (4))) = (0))) stmt (Cosine8  ((cos ((τ) / (8))) = ((√ (2)) / (2)))) stmt (Sine8  ((sin ((τ) / (8))) = ((√ (2)) / (2)))) 