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1/1x4+1/2x5+1/3x6+……+1/9x12
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1/1x4+1/2x5+1/3x6+……+1/9x12
▼优质解答
答案和解析
1/1x4+1/2x5+1/3x6+……+1/9x12
=(1-1/4)/3+(1/2-1/5)/3+(1/3-1/6)/3+...+(1/9-1/12)/3
=[(1+1/2+1/3+...+1/9)-(1/4+1/5+1/6+...+1/12)]/3
=[(1+1/2+1/3)-(1/10+1/11+1/12)]/3
=343/660
如果不懂,祝学习愉快!
=(1-1/4)/3+(1/2-1/5)/3+(1/3-1/6)/3+...+(1/9-1/12)/3
=[(1+1/2+1/3+...+1/9)-(1/4+1/5+1/6+...+1/12)]/3
=[(1+1/2+1/3)-(1/10+1/11+1/12)]/3
=343/660
如果不懂,祝学习愉快!
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