WCpqr79 WCpqr792 WCpzero WCpzero2 WDka WDka2 WRpzero WRpzero2

WRpzero() Function WRpzero ( N As  Long, A As  Variant  ) Roots of a polynomial with real coefficients by Newton method (complex number representation in Excel format) Purpose WRpzero computes all roots of a polynomial p(z) with real coefficients by Newton method. p(z) = a0*z^n + a1*z^(n-1) + ... + an The obtained complex roots are represented in Excel complex number format (e.g. 2.5+1i). This complex value can be used by Excel worksheet functions related to complex numbers. Returns N+1 x 2 Column 1 Columns 2 Rows 1 to N Roots Error bound for the computed roots Row N+1 Return code Number of iterations performed to converge Return code. = 0: Successful exit. = 1: Maximum number of iterations (25*N) exceeded. Best current estimates of the zeros are returned. Error bounds are not calculated. Parameters [in] N Degree of polynomial. (N >= 1) [in] A (N+1 x 1) or (1 x N+1) Real coefficients a0 to an of polynomial a0 x^n + a1 x^(n-1) + … + a(n-1)x + an. Reference SLATEC Example Solve the following algebraic equation. x^5 + 2*x^3 + 2*x^2 - 15*x + 10 = 0 The exact solutions are 1(multiple root), -2, and ±√5i.