case mk
K : Type u_1
inst✝¹ : LinearOrderedField K
inst✝ : FloorRing K
v : K
n : ℕ
b✝ : ℤ
fr : K
stream_nth_eq : IntFractPair.stream v n = some { b := b✝, fr := fr }
nth_fr_eq_zero : { b := b✝, fr := fr }.fr = 0
⊢ IntFractPair.stream v (n + 1) = none
K : Type u_1
inst✝¹ : LinearOrderedField K
inst✝ : FloorRing K
v : K
n : ℕ
ifp_n : IntFractPair K
stream_nth_eq : IntFractPair.stream v n = some ifp_n
nth_fr_eq_zero : ifp_n.fr = 0
⊢ IntFractPair.stream v (n + 1) = none
cases' ifp_n with _ fr
case mk
K : Type u_1
inst✝¹ : LinearOrderedField K
inst✝ : FloorRing K
v : K
n : ℕ
b✝ : ℤ
fr : K
stream_nth_eq : IntFractPair.stream v n = some { b := b✝, fr := fr }
nth_fr_eq_zero : fr = 0
⊢ IntFractPair.stream v (n + 1) = none
case mk
K : Type u_1
inst✝¹ : LinearOrderedField K
inst✝ : FloorRing K
v : K
n : ℕ
b✝ : ℤ
fr : K
stream_nth_eq : IntFractPair.stream v n = some { b := b✝, fr := fr }
nth_fr_eq_zero : { b := b✝, fr := fr }.fr = 0
⊢ IntFractPair.stream v (n + 1) = none
change fr = 0 at nth_fr_eq_zero
no goals
case mk
K : Type u_1
inst✝¹ : LinearOrderedField K
inst✝ : FloorRing K
v : K
n : ℕ
b✝ : ℤ
fr : K
stream_nth_eq : IntFractPair.stream v n = some { b := b✝, fr := fr }
nth_fr_eq_zero : fr = 0
⊢ IntFractPair.stream v (n + 1) = none
simp [IntFractPair.stream, stream_nth_eq, nth_fr_eq_zero]