θ_r = a₀ + a₁ α_r + a₂ α_r² .... + a_{n— 1} α_r^{n — 1}

D = ${\displaystyle {\begin{vmatrix}a_{0}&a_{1}&\cdots &a_{\mathrm {n} -1}\\a_{1}&a_{2}&\cdots &a_{0}\\\cdots &\cdots &\cdots &\cdots \\\cdots &\cdots &\cdots &\cdots \\a_{\mathrm {n} -1}&a_{0}&\cdots &a_{\mathrm {n} -2}\end{vmatrix}}}$,     Δ = ${\displaystyle {\begin{vmatrix}1&1&1&\cdots &1\\1&\alpha _{1}&\alpha _{2}&\cdots &\alpha _{\mathrm {n} -1}\\1&\alpha _{1}^{2}&\alpha _{2}^{2}&\cdots &\alpha _{\mathrm {n} -1}^{2}\\\cdots &\cdots &\cdots &\cdots &\cdots \\1&\alpha _{1}^{\mathrm {n} -1}&\alpha _{2}^{\mathrm {n} -1}&\cdots &\alpha _{\mathrm {n} -1}^{\mathrm {n} -1}\end{vmatrix}}}$.