1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)2.100²-99²+98²-97²+······+2²-13.(10的12次方+25)-(10的12次方-25)=10的n次方
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/23 21:05:26
![1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)2.100²-99²+98²-97²+······+2²-13.(10的12次方+25)-(10的12次方-25)=10的n次方](/uploads/image/z/1325291-59-1.jpg?t=1.%EF%BC%881-1%2F2%26sup2%3B%EF%BC%89%EF%BC%881-1%2F3%26sup2%3B%EF%BC%89%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%EF%BC%881-1%2F9%26sup2%3B%EF%BC%89%EF%BC%881-1%2F10%26sup2%3B%EF%BC%892.100%26sup2%3B-99%26sup2%3B%2B98%26sup2%3B-97%26sup2%3B%2B%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%2B2%26sup2%3B-13.%EF%BC%8810%E7%9A%8412%E6%AC%A1%E6%96%B9%2B25%EF%BC%89-%EF%BC%8810%E7%9A%8412%E6%AC%A1%E6%96%B9-25%EF%BC%89%3D10%E7%9A%84n%E6%AC%A1%E6%96%B9)
1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)2.100²-99²+98²-97²+······+2²-13.(10的12次方+25)-(10的12次方-25)=10的n次方
1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)
2.100²-99²+98²-97²+······+2²-1
3.(10的12次方+25)-(10的12次方-25)=10的n次方
1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)2.100²-99²+98²-97²+······+2²-13.(10的12次方+25)-(10的12次方-25)=10的n次方
1.
=(1-1/2)(1+1/2) (1-1/3)(1+1/3) .(1-1/10)(1+1/10)
=1/2 * 3/2 * 2/3 *4/3 *3/4*.9/10*11/10
=1/2*11/10
=11/20
2.100²-99²+98²-97²+······+2²-1
=(100-99)(100+99) + (98-97)*(98+97) +.(2-1)(2+1)
=100+99+98+97+...+2+1
=101*100/2
=5050
3.(10的12次方+25)-(10的12次方-25)=10的n次方 【看不明白】
(10的12次方+25)-(10的12次方-25)=10的12次方+25 -10的12次方+25=50
1.(1-1/2²)(1-1/3²)······(1-1/9²)(1-1/10²)
2.100²-99²+98²-97²+······+2²-1
3.(10^12+25)-(10^12-25)=10^n
居然有那么难度的饿
=(100+99)(100-99)+(98+97)(98-97)+……(2+1)(2-1)
=100+99+98+……+2+1
=101*50
=5050
1.原式=(1+1/2)(1-1/2)(1+1/3)(1-1/3)┄┅(1+1/10)(1-1/10)=1/2×3/2×4/3x2/3x5/4x3/4
2.原式=(100+99)(100-99)+┅(2+1)(2-1)=199+195+191┅+3=