The approximation signal "≈" I exploit for decimal approximations with tilde "~" remaining a rougher approximation. When the algebraic components for $b, c$ is simple to compute, the algebraic method for $a$ is very difficult to compute. As a result the modern method relies on numerical calculation of $a$. But https://cristianrsrnj.aboutyoublog.com/42263388/por-qué-es-bueno-leer-el-tarot-an-overview