equal
deleted
inserted
replaced
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> |