Theorem: Real.exp_bound'
File: Mathlib/Data/Complex/Exponential.lean

tactic: have h3 : |x| = x := by simpa
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: have h4 : |x| ≤ 1 := by rwa [h3]
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: have h' := Real.exp_bound h4 hn
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ |x| ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: rw [h3] at h'
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ |x| ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: have h'' := (abs_sub_le_iff.1 h').1
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
h'' : rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: have t := sub_le_iff_le_add'.1 h''
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
h'' : rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
h'' : rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
t : rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)

tactic: simpa [mul_div_assoc] using t
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
h4 : |x| ≤ 1
h' : |rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial| ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
h'' : rexp x - ∑ m ∈ range n, x ^ m / ↑m.factorial ≤ x ^ n * (↑n.succ / (↑n.factorial * ↑n))
t : rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n.succ / (↑n.factorial * ↑n))
⊢ rexp x ≤ ∑ m ∈ range n, x ^ m / ↑m.factorial + x ^ n * (↑n + 1) / (↑n.factorial * ↑n)
state_after: no goals

tactic: simpa
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
⊢ |x| = x
state_after: no goals

tactic: rwa [h3]
state_before: x : ℝ
h1 : 0 ≤ x
h2 : x ≤ 1
n : ℕ
hn : 0 < n
h3 : |x| = x
⊢ |x| ≤ 1
state_after: no goals