1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/20 22:33:07
![1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?](/uploads/image/z/2777589-45-9.jpg?t=1%2F1x3%2B1%2F3x5%2B1%2F5x7%2B1%2F7x9%2B1%2F9x11%3D%3F)
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
=1/2×(1-1/3+1/3-1/5+1/5-1/7+17-1/9+1/9-1/11)
=1/2×(1-1/11)
=1/2×10/11
=5/11
1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+1/(9×11)
=(1/2)(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)
=(1/2)(1-1/11)
=(1/2)(10/11)
=5/11