11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/17 18:41:42
![11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?](/uploads/image/z/66828-12-8.jpg?t=11%2B13%2B15%2B17%2B19%2B21%2B23%2B25%2B27%2B29%2B31%2B33%2B35%2B37%2B39%2B41%2B43%2B45%2C%E8%AE%A1%E7%AE%97%E6%97%B6%E8%A7%84%E5%BE%8B%3F)
11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?
11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?
11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?
等差数列
(11+45)*18/2=504
等差数列啊
S=(a1+an)*n/2=(11+45)*18/2=56*9=504
这是等差数列,用首项加末项,乘以项数/2
11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45=(27+29)/2X18=504
11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45=(11+45)x18/2=504
等差数列,前n项和公式s=(a1+an)n/2=(11+45)*18/2=504
等差数列,用首项加末项,乘以项数/2
(11+45)*18/2=56*9=504