theorem
proved
term proof
jcost_cosh_is_gamma_minus_one
show as:
view Lean formalization →
formal statement (Lean)
50theorem jcost_cosh_is_gamma_minus_one (theta : ℝ) :
51 Jcost (Real.cosh theta) = Real.cosh theta - 1 := by
proof body
Term-mode proof.
52 unfold Jcost
53 have h_cosh_pos : 0 < Real.cosh theta := Real.cosh_pos theta
54 rw [Real.cosh_inv (Real.cosh theta) h_cosh_pos.ne']
55 ring
56
57/-- Mass-energy: m·c² on the φ-ladder at rung r. -/