函式項級數
![一致收斂](/img/2/e26/nBnauM3XzEjNxEjMycDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL3AzLwYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
設 是定義在數集I上的函式列,表達式
![一致收斂](/img/8/84c/nBnauM3X2IDM4AzNwcDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL3AzL1YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
稱為定義在I上的函式項級數,而
![一致收斂](/img/b/08c/nBnauM3XxETNzMTM4ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL0AzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
稱為函式項級數的部分和。
![一致收斂](/img/3/f67/nBnauM3X0ATMwUjMxYzM2EzM1UTM1QDN5MjM5ADMwAjMwUzL2MzL0QzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![一致收斂](/img/7/3fe/nBnauM3X0MTNyEzNwATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzLzczLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![一致收斂](/img/1/96f/nBnauM3XyEjN4ITNyMTMzEDN0UTMyITNykTO0EDMwAjMwUzLzEzLxczLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/6/593/nBnauM3X2YDMxIjN4ETOwMzM1UTM1QDN5MjM5ADMwAjMwUzLxkzL0UzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/7/3fe/nBnauM3X0MTNyEzNwATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzLzczLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![一致收斂](/img/1/96f/nBnauM3XyEjN4ITNyMTMzEDN0UTMyITNykTO0EDMwAjMwUzLzEzLxczLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/6/593/nBnauM3X2YDMxIjN4ETOwMzM1UTM1QDN5MjM5ADMwAjMwUzLxkzL0UzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
對於每一個 ,如果常數項級數 收斂,則 稱為函式項級數 的收斂點;如果常數項級數 發散,則 稱為函式項級數 的發散點。
定義
![一致收斂](/img/9/2db/nBnauM3X3UDO1IzM5IjN5ADN0UTMyITNykTO0EDMwAjMwUzLyYzLzgzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/9/2db/nBnauM3X3UDO1IzM5IjN5ADN0UTMyITNykTO0EDMwAjMwUzLyYzLzgzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/b/6cc/nBnauM3X3QzM5YjNzMjM0EDN0UTMyITNykTO0EDMwAjMwUzLzIzL3EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![一致收斂](/img/8/db9/nBnauM3X1EjN4YTO0EDN2EzM1UTM1QDN5MjM5ADMwAjMwUzLxQzLxEzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![一致收斂](/img/7/a96/nBnauM3X1gTM2cDMyATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL4czLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/6/06c/nBnauM3XxYTNyADO1gzM2EzM1UTM1QDN5MjM5ADMwAjMwUzL4MzL1YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![一致收斂](/img/b/6cc/nBnauM3X3QzM5YjNzMjM0EDN0UTMyITNykTO0EDMwAjMwUzLzIzL3EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
若對任給的正數 ,不論它如何小,常能找到一個只依賴於 但與 無關的數 ,使對 以及區間 中的每一 ,都有
![一致收斂](/img/f/8a5/nBnauM3X2ATM0QTN1ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL4czLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![一致收斂](/img/6/240/nBnauM3XzYTN4cjN4ETOwMzM1UTM1QDN5MjM5ADMwAjMwUzLxkzL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/6/06c/nBnauM3XxYTNyADO1gzM2EzM1UTM1QDN5MjM5ADMwAjMwUzL4MzL1YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
則稱級數 在區間 上一致收斂。
判別法
柯西準則
![一致收斂](/img/f/0a6/nBnauM3XyczM5MTO4ETNyMzM1UTM1QDN5MjM5ADMwAjMwUzLxUzLyMzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
函式列 在數集D上一致收斂的充要條件是:
![一致收斂](/img/9/2db/nBnauM3X3UDO1IzM5IjN5ADN0UTMyITNykTO0EDMwAjMwUzLyYzLzgzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/a/632/nBnauM3XycDN4cDM0QDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL0AzL4AzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![一致收斂](/img/9/3b0/nBnauM3X0gzN5EjMxMDO4EDN0UTMyITNykTO0EDMwAjMwUzLzgzL1YzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![一致收斂](/img/3/f8f/nBnauM3X2ITNwYTN2YDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL2AzL2YzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
對任給>0,總存在正整數N,使得當 時,對一切 ,都有 。
餘項準則
![一致收斂](/img/f/0a6/nBnauM3XyczM5MTO4ETNyMzM1UTM1QDN5MjM5ADMwAjMwUzLxUzLyMzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
函式列 在數集D上一致收斂的充要條件是 :
![一致收斂](/img/f/b2f/nBnauM3XxMTM4czNwcDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL3AzLzczLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
Weierstrass判別法
![一致收斂](/img/d/b4e/nBnauM3XycDNwEjNykzN5ADN0UTMyITNykTO0EDMwAjMwUzL5czL1MzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![一致收斂](/img/a/6b2/nBnauM3X3YjMxMzM2YDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL2AzLyMzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/a/351/nBnauM3X3UTN4cjNzgzMxMzM1UTM1QDN5MjM5ADMwAjMwUzL4MzL2UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/6/593/nBnauM3X2YDMxIjN4ETOwMzM1UTM1QDN5MjM5ADMwAjMwUzLxkzL0UzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
若對充分大的n,恆有實數 ,使得 對E上任意的x都成立,並且數項級數 收斂,則 在E上一致收斂。
Abel判別法
如果
![一致收斂](/img/1/e0f/nBnauM3X0QDNwAzN1ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL3AzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
1)函式項級數 在E上一致收斂
![一致收斂](/img/e/7e4/nBnauM3XzITN4QDO2QTOwMzM1UTM1QDN5MjM5ADMwAjMwUzL0kzL3UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/7/4b5/nBnauM3X2EDOyUzM4UDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL1AzL2EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![一致收斂](/img/e/7e4/nBnauM3XzITN4QDO2QTOwMzM1UTM1QDN5MjM5ADMwAjMwUzL0kzL3UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/c/a57/nBnauM3XwATMzYDM1UDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL1AzLxQzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
2)對每一固定的 , 隨n而單調,而對任意的 和n,有 (不依賴於x和n的定數)
![一致收斂](/img/d/6b5/nBnauM3XxYDMxEjM2ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzLwMzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
那么 在E上一致收斂。
Dirichlet判別法
如果
![一致收斂](/img/1/e0f/nBnauM3X0QDNwAzN1ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL3AzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/3/379/nBnauM3XxADN1EDN0YDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL2AzLxIzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
1)函式項級數 的部分和 在E上一致有界
![一致收斂](/img/e/7e4/nBnauM3XzITN4QDO2QTOwMzM1UTM1QDN5MjM5ADMwAjMwUzL0kzL3UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![一致收斂](/img/7/4b5/nBnauM3X2EDOyUzM4UDM5YzM1UTM1QDN5MjM5ADMwAjMwUzL1AzL2EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![一致收斂](/img/f/216/nBnauM3X4MjN3MDOxITM5YzM1UTM1QDN5MjM5ADMwAjMwUzLyEzL2AzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
2)對每一 , 隨n而單調,並且函式序列 在E上一致收斂於零
![一致收斂](/img/d/6b5/nBnauM3XxYDMxEjM2ATM5YzM1UTM1QDN5MjM5ADMwAjMwUzLwEzLwMzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
那么 在E上一致收斂。