(1)3/2+7/6+13/12+21/20+...111/110 (2)1-2+3-4+.-200+201
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(1)3/2+7/6+13/12+21/20+...111/110 (2)1-2+3-4+.-200+201
(1)3/2+7/6+13/12+21/20+...111/110 (2)1-2+3-4+.-200+201
(1)3/2+7/6+13/12+21/20+...111/110 (2)1-2+3-4+.-200+201
(1) 3/2+7/6+13/12+21/20+...111/110
=1+1/(1*2)+1+1/(2*3)+1+1/(3*4)+1+1/(4*5)+...+1+1/(10*11)
=10+1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+...+1/(10*11)
=10+(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/10-1/11)
=10+1-1/11
=10又(10/11)
(2)1-2+3-4+.-200+201
=(1-2)+(3-4)+...+(199-200)+201
=-1*200/2 +201
=-100+201
=101
1,10又11分之10
2,101
(2)原式=1+1+。。。+1(-2+3=+1)
=1*【(201-1)/2+1】
=1*101
=101
(2)1-2+3-4+5-6+。。。。。。+199-200+201
=201-200+199-198+197-196+。。。。。。+7-6+5-4+3-2+1
=(201-200)+(199-198)+(197-196)+。。。。。。(7-6)+(5-4)+(3-2)+1
=1+1+1+1+1+。。。。。。+1
=101