a) Tìm cặp số nguyên n sao cho n chia hết cho 2n - 4
b) Tính tổng S = 1 - 2 + 22 - 23 + 24 - 25 + 26 - 27 + ... - 22013 + 22014
c) Chứng minh :
\(\dfrac{1}{2}\) - \(\dfrac{1}{3}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{6}\) - \(\dfrac{1}{7}\) + ... + \(\dfrac{1}{2012}\) - \(\dfrac{1}{2013}\) + \(\dfrac{1}{2014}\) < \(\dfrac{2}{5}\)
đó giúp mk đi mà![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)
à, mk quên chưa nói là ai giúp mk sẽ được luôn 2SP đó![vui vui](https://hoc24.vn/media/cke24/plugins/smiley/images/vui.png)
![ok ok](https://hoc24.vn/media/cke24/plugins/smiley/images/ok.png)
giúp mk nha![ok ok](https://hoc24.vn/media/cke24/plugins/smiley/images/ok.png)
cảm ơn nhiều!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
những thánh giỏi toán ơi giúp mk được ko
mk năn nỉ đó![khocroi khocroi](https://hoc24.vn/media/cke24/plugins/smiley/images/khocroi.png)