theorem
proved
tactic proof
pi_pow5_gt_d6
show as:
view Lean formalization →
formal statement (Lean)
216theorem pi_pow5_gt_d6 : (306.0193 : ℝ) < pi ^ 5 := by
proof body
Tactic-mode proof.
217 have h := Real.pi_gt_d6 -- 3.141592 < π
218 have hpos : 0 < pi := Real.pi_pos
219 have h1 : (3.141592 : ℝ) ^ 5 < pi ^ 5 := by
220 have hle : (3.141592 : ℝ) ≤ pi := le_of_lt h
221 have hlo : (0 : ℝ) < 3.141592 := by norm_num
222 nlinarith [sq_nonneg pi, sq_nonneg (pi - 3.141592), mul_self_nonneg pi,
223 mul_self_nonneg (pi ^ 2), mul_self_nonneg (pi ^ 2 - 3.141592 ^ 2)]
224 calc (306.0193 : ℝ) < (3.141592 : ℝ) ^ 5 := by norm_num
225 _ < pi ^ 5 := h1
226
227/-- π⁵ < 306.0199 (using π < 3.141593) -/