1/1×3+1/3×5+1/5×7······﹢1/47×49

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1/1×3+1/3×5+1/5×7······﹢1/47×49

1/1×3+1/3×5+1/5×7······﹢1/47×49
=1/2×(1-1/3)+1/2×(1/3-1/5)+...+1/2×(1/47-1/49)
=1/2×(1-1/'3+1/3-1/5+1/5-1/7+...+1/47-1/49)
=1/2×(1-1/49)
=24/49

1/1×3+1/3×5+1/5×7······﹢1/47×49 1+2+3+4+5········+n,=多少? (1)5+10+15+20+25+···+85+90+95+100(2)﹙1+3+5+7+···+1991﹚-﹙2+4+6+8+···+1990﹚ 1×2+3×4+5×6+7×8······+199×200= 利用等差规律计算一、计算:1+3+5+···+197+99;81+79+···+13+11;1-2+3-4+5-6+···+2009-2010+2011.二、按一定规律排列的算式:4+2,5+8,6+14,7+20,···,那么第100个算式是 1×3分之1+3×5分之1+···+2007×2009分之1 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 计算:1+2-3-4+5+6-7-8+···+2013+2014-2015-2016 1/2×5+1/3×5+1/8×11······﹢1/20×23 简便运算4题1+2×2+3×4+4×8+5×16····+11×1024+12×2048切记,1:1+2×2+3×4+4×8+5×16····+11×1024+12×2048=2:1×1+2×3+3×5+4×7+·····+99×197=3:1的平方+3的平方+5的平方+7的平方…+ c语言编程题,计算1×2×3+3×4×5+······+99×100×101的值 简单数学题5/(1*2*3)+6/(2*3*4)+7/(3*4*5)+···+2006/(2002*2003*2004) 1又1/2+3又1/4+5又1/8+···+[(2n-1)+1/2的n次方]= 1+(﹣2)+(﹣3)+4+5+(﹣6)···+2008+2009 现在! 计算:1/1·5+1/3·7+1/5·9+···+1/21·25 1+2+3+4+···+n=? 计算1-3+5-7+9-11+··········+97-99= 一道数学题 简算 1/1× 2× 3+1/2×3×4+1/3×4×5+······+1/9×10×11=?