1+3+5= 1+3+5+7= 1+3+5+7+.+(2n-1)=
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1+3+5= 1+3+5+7= 1+3+5+7+.+(2n-1)=
![](http://img.wesiedu.com/upload/1/21/12175d71431454977953dd643d09bce1.jpg)
![](http://img.wesiedu.com/upload/1/21/12175d71431454977953dd643d09bce1.jpg)
![1+3+5= 1+3+5+7= 1+3+5+7+.+(2n-1)=](/uploads/image/z/17622242-26-2.jpg?t=1%2B3%2B5%3D+1%2B3%2B5%2B7%3D+1%2B3%2B5%2B7%2B.%2B%EF%BC%882n-1%EF%BC%89%3D)
有图可知每一个式子计算结果都是一个完全平方数,是最后一个数与1的和的一半的平方.
1=1^2=1 [(1+1)/2]^2=1
1+3=2^2=4 [(3+1)/2]^2=4
1+3+5= 3^2=9 [(5+1)/2]^2=9
1+3+5+7= 4^2=16 [(7+1)/2]^2=16
1+3+5+9= 5^2=25 [(9+1)/2]^2=25
……
1+3+5+7+.+(2n-1)= [(2n-1+1)/2]^2=n^2
![](http://img.wesiedu.com/upload/0/f0/0f0b90c07eaaf75b87f0d6c426d7b2be.jpg)
1=1^2=1 [(1+1)/2]^2=1
1+3=2^2=4 [(3+1)/2]^2=4
1+3+5= 3^2=9 [(5+1)/2]^2=9
1+3+5+7= 4^2=16 [(7+1)/2]^2=16
1+3+5+9= 5^2=25 [(9+1)/2]^2=25
……
1+3+5+7+.+(2n-1)= [(2n-1+1)/2]^2=n^2
![](http://img.wesiedu.com/upload/0/f0/0f0b90c07eaaf75b87f0d6c426d7b2be.jpg)
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
3n²-n=1 求6n³+7n²-5n+2014
M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64
若3n^2-n=1,求6n^3+7n^2-5n+2003的值
-1+3-5+...+(-1)^n(2n-1)=(-1)^n X n
1除以(n+3)(n+4)+1除以(n+4)(n+5)+、、、1除以(n+10)(n+11)=?
用数学归纳法证明:1*3*5*.*(2n-1)*2^n=(n+1)(n+2).(2n)(n属于N*)
3n平方-n=1,求6n三次方+7n平方-5n+2014的值,
已知3n²-n=1,求6n³+7 n²-5n+2003的值
用数学归纳法证明:1-3+5-7+...+(-1)^N-1(2N-1)=(-1)^N-1*N
1+3+5+7+9+.+(2n-1)+(2n+1)+(2n+3)=
求和:Sn=1-3x+5x^2-7x^3+.+(2n+1)(-x)^n(n属于N*)