为什么x+x^3+x^5+…+x^(2n+1)+…=x/(1-x^2)?要推导过程,

为什么x+x^3+x^5+…+x^(2n+1)+…=x/(1-x^2)? 为什么x+x^3+x^5+…+x^(2n+1)+…=x/(1-x^2)?要推导过程, 求和x+x^2+x^3+…x^n= 求和：Sn=1+3x+5x*x+7x*x*x+……+（2n-1)x^n-1 (x不为0和1） (4x^n-2x^n-1-3x^n+2)÷（-5x^n-1) x^n-1(3x^n+4x^n+1-5x^n+2) (-x)^3x^n-1+x^2n(-x)^3 求和Sn=(x-1)+(x^3-2)+(x^5-3)+(x^7-4)+…+(x^2n-1-n) *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || x^n*x^n+1*(-x)^2n*x+(-x)^2n+3x^2n-2*x y=|x-1|+|x-2|+|x-3|+|x-4|+|x-5|+|x-6|……+|x-99|+|x-100|+50n的最小值 有关泰勒公式的证明?泰勒中值定理中 f(x)=f(x.)+f'(x.)(x-x.)+f''(x.)/2!(x-x.)^2,+f'''(x.)/3!(x-x.)^3+……+f(n)(x.)/n!(x-x.)^n+Rn 这个等式怎么证明?f(x)为什么可以写成这样? 化简:1+x+x^3+x^5+…+x^2n+7 X,2X,4X,8X,16X,32X,.第N个单项式为什么 填九宫格帮帮忙.x x 6 x x 7 x x 98 x x x 3 x 1 x x 9 x x 6 x 5 x 3 x x x 3 x x x x 1 8x x x 9 x 1 x x x2 1 x x x x 6 x x x 6 x 7 x 3 x x 1 x x 9 x 2 x x x 47 x x 8 x x 5 x x 求 4/(x+1)(x+3) + 4/(x+3)(x+5) +.+ 4/(x+2n-1)(x+2n+1) x^2n-3x^n 两题填空题.x+y=-3,则5-2x-2y=_________.观察下列各式：(x-1)(x+1)=x^2-1,(x-1)(x^2+x+1)=x^3-1,(x-1)(x^3+x^2+x+1)…根据前面的各式规律可得(x-1)(x^n-x^n-1+…+x+1)=_______.