一道关于运算的数学题1+2=(1+2)*2/2=3 1+2+3=(1+3)*3/2=61+2+3+4=(1+4)*4/2=10…1+2+3+4+……+n=(1+n)*n/2(1)计算1+3+5+……+2n-3+2n-1(2)计算2+4+6+……2n-2+2n
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![一道关于运算的数学题1+2=(1+2)*2/2=3 1+2+3=(1+3)*3/2=61+2+3+4=(1+4)*4/2=10…1+2+3+4+……+n=(1+n)*n/2(1)计算1+3+5+……+2n-3+2n-1(2)计算2+4+6+……2n-2+2n](/uploads/image/z/4520960-8-0.jpg?t=%E4%B8%80%E9%81%93%E5%85%B3%E4%BA%8E%E8%BF%90%E7%AE%97%E7%9A%84%E6%95%B0%E5%AD%A6%E9%A2%981%2B2%3D%281%2B2%29%2A2%2F2%3D3+1%2B2%2B3%3D%EF%BC%881%2B3%EF%BC%89%2A3%2F2%3D61%2B2%2B3%2B4%3D%EF%BC%881%2B4%EF%BC%89%2A4%2F2%3D10%E2%80%A61%2B2%2B3%2B4%2B%E2%80%A6%E2%80%A6%2Bn%3D%EF%BC%881%2Bn%EF%BC%89%2An%2F2%EF%BC%881%EF%BC%89%E8%AE%A1%E7%AE%971%2B3%2B5%2B%E2%80%A6%E2%80%A6%2B2n-3%2B2n-1%EF%BC%882%EF%BC%89%E8%AE%A1%E7%AE%972%2B4%2B6%2B%E2%80%A6%E2%80%A62n-2%2B2n)
一道关于运算的数学题1+2=(1+2)*2/2=3 1+2+3=(1+3)*3/2=61+2+3+4=(1+4)*4/2=10…1+2+3+4+……+n=(1+n)*n/2(1)计算1+3+5+……+2n-3+2n-1(2)计算2+4+6+……2n-2+2n
一道关于运算的数学题
1+2=(1+2)*2/2=3
1+2+3=(1+3)*3/2=6
1+2+3+4=(1+4)*4/2=10
…
1+2+3+4+……+n=(1+n)*n/2
(1)计算1+3+5+……+2n-3+2n-1
(2)计算2+4+6+……2n-2+2n
一道关于运算的数学题1+2=(1+2)*2/2=3 1+2+3=(1+3)*3/2=61+2+3+4=(1+4)*4/2=10…1+2+3+4+……+n=(1+n)*n/2(1)计算1+3+5+……+2n-3+2n-1(2)计算2+4+6+……2n-2+2n
先做第二问
2+4+6+……2n-2+2n
=2×(1+2+3+4+……+n)
=2×(1+n)*n/2
=(1+n)*n
第一问就简单了
1+3+5+……+2n-3+2n-1
=(2-1)+(4-1)+(6-1)+……+2n-1
= (1+n)*n-n
=n*(n+1-1)
=n^2