求解legendre多项式的系数，N各点对应N阶legendre多项式，有N+1各多项式系数，采用递推公式，40阶后误差较大。-Solving legendre polynomials, N points corresponding to N-order legendre polynomial, there are N+1 coefficients of the polynomial, using recursive formulas, after the error of order 40 more.