数学计算,要简便————————
1/1×2-5/2×3+1/3×4-19/4×5+1/5×6-41/6×7=???
参考答案:1/1×2-5/2×3+1/3×4-19/4×5+1/5×6-41/6×7
=1/1*2-[1-1/2*3]+1/3*4-[1-1/4*5]+1/5*6-[1-1/6*7]
=[1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7]-3
=1-1/7-3
=-2又1/7
1/1×2-5/2×3+1/3×4-19/4×5+1/5×6-41/6×7=???
参考答案:1/1×2-5/2×3+1/3×4-19/4×5+1/5×6-41/6×7
=1/1*2-[1-1/2*3]+1/3*4-[1-1/4*5]+1/5*6-[1-1/6*7]
=[1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7]-3
=1-1/7-3
=-2又1/7