1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49=几的平方
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/04 23:16:07
![1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49=几的平方](/uploads/image/z/67856-32-6.jpg?t=1%2B3%2B5%2B7%2B9%2B11%2B13%2B15%2B17%2B19%2B21%2B23%2B25%2B27%2B29%2B31%2B33%2B35%2B37%2B39%2B41%2B43%2B45%2B47%2B49%3D%E5%87%A0%E7%9A%84%E5%B9%B3%E6%96%B9)
1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49=几的平方
1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49=几的平方
1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49=几的平方
Sn=1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49
Sn=1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49
2Sn=(1+49)*2+(3+47)*2+(5+45)*2+……+(25+25)*2
Sn=25*50/2
=25²
原式=(1+49)/2*(49+1)/2=25²
∵1+3+5+......+41+43+45+47+49=625,且“根号625”=25
∴答案是25
是25的平方