src/HOL/Hyperreal/Deriv.thy
changeset 22613 2f119f54d150
parent 21810 b2d23672b003
child 22641 a5dc96fad632
equal deleted inserted replaced
22612:1f017e6a0395 22613:2f119f54d150
   120   hence "(\<lambda>h. f(x+h)) -- 0 --> f x"
   120   hence "(\<lambda>h. f(x+h)) -- 0 --> f x"
   121     by (simp only: isCont_iff)
   121     by (simp only: isCont_iff)
   122   hence "(\<lambda>h. f(x+h) * ((g(x+h) - g x) / h) +
   122   hence "(\<lambda>h. f(x+h) * ((g(x+h) - g x) / h) +
   123               ((f(x+h) - f x) / h) * g x)
   123               ((f(x+h) - f x) / h) * g x)
   124           -- 0 --> f x * E + D * g x"
   124           -- 0 --> f x * E + D * g x"
   125     by (intro LIM_add LIM_mult2 LIM_const DERIV_D f g)
   125     by (intro LIM_add LIM_mult LIM_const DERIV_D f g)
   126   thus "(\<lambda>h. (f(x+h) * g(x+h) - f x * g x) / h)
   126   thus "(\<lambda>h. (f(x+h) * g(x+h) - f x * g x) / h)
   127          -- 0 --> f x * E + D * g x"
   127          -- 0 --> f x * E + D * g x"
   128     by (simp only: DERIV_mult_lemma)
   128     by (simp only: DERIV_mult_lemma)
   129 qed
   129 qed
   130 
   130 
   202   next
   202   next
   203     from der have "(\<lambda>z. (f z - f x) / (z - x)) -- x --> D"
   203     from der have "(\<lambda>z. (f z - f x) / (z - x)) -- x --> D"
   204       by (unfold DERIV_iff2)
   204       by (unfold DERIV_iff2)
   205     thus "(\<lambda>z. - (inverse (f z) * ((f z - f x) / (z - x)) * inverse (f x)))
   205     thus "(\<lambda>z. - (inverse (f z) * ((f z - f x) / (z - x)) * inverse (f x)))
   206           -- x --> ?E"
   206           -- x --> ?E"
   207       by (intro LIM_mult2 LIM_inverse LIM_minus LIM_const lim_f neq)
   207       by (intro LIM_mult LIM_inverse LIM_minus LIM_const lim_f neq)
   208   qed
   208   qed
   209 qed
   209 qed
   210 
   210 
   211 lemma DERIV_divide:
   211 lemma DERIV_divide:
   212   "\<lbrakk>DERIV f x :> D; DERIV g x :> E; g x \<noteq> 0\<rbrakk>
   212   "\<lbrakk>DERIV f x :> D; DERIV g x :> E; g x \<noteq> 0\<rbrakk>