> 数学 >
已知1+2+3·······+31+32+33=17乘33,求1-3+2-6+3-9+········+31-93+32-96+33-99的值,
人气:470 ℃ 时间:2019-08-20 13:52:49
解答
1-3+2-6+3-9+········+31-93+32-96+33-99
=1+2+3+····+33-(3+6+9+····+99)
=1+2+3+····+33-3*(1+2+3+····+33)
=-2*(1+2+3+····+33)
=-2*17*33
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版