src/HOL/ex/Gauge_Integration.thy
changeset 49962 a8cc904a6820
parent 46501 fe51817749d1
child 51480 3793c3a11378
equal deleted inserted replaced
49961:d3d2b78b1c19 49962:a8cc904a6820
   519           mult_assoc [symmetric])
   519           mult_assoc [symmetric])
   520 apply (subgoal_tac "inverse (z - x) * (f z - f x - f' x * (z - x)) 
   520 apply (subgoal_tac "inverse (z - x) * (f z - f x - f' x * (z - x)) 
   521                     = (f z - f x) / (z - x) - f' x")
   521                     = (f z - f x) / (z - x) - f' x")
   522  apply (simp add: abs_mult [symmetric] mult_ac diff_minus)
   522  apply (simp add: abs_mult [symmetric] mult_ac diff_minus)
   523 apply (subst mult_commute)
   523 apply (subst mult_commute)
   524 apply (simp add: left_distrib diff_minus)
   524 apply (simp add: distrib_right diff_minus)
   525 apply (simp add: mult_assoc divide_inverse)
   525 apply (simp add: mult_assoc divide_inverse)
   526 apply (simp add: left_distrib)
   526 apply (simp add: distrib_right)
   527 done
   527 done
   528 
   528 
   529 lemma lemma_straddle:
   529 lemma lemma_straddle:
   530   assumes f': "\<forall>x. a \<le> x & x \<le> b --> DERIV f x :> f'(x)" and "0 < e"
   530   assumes f': "\<forall>x. a \<le> x & x \<le> b --> DERIV f x :> f'(x)" and "0 < e"
   531   shows "\<exists>g. gauge {a..b} g &
   531   shows "\<exists>g. gauge {a..b} g &