# Bug for Cubics -> True in Eigenvalues?

Let's consider the simple code

Eigenvalues[{{a, b, c}, {d, e, f}, {g, h, i}}, Cubics -> True]
(* {Root[<<1>> &, 1],Root[<<1>> &, 2],Root[<<1>> &, 3]} *)


Using the option Cubics -> True, I expected the Root[] expressed in terms of radicals. Why it's not the case?

The same happens considering a 4 by 4 matrix and the option Quartics -> True.

P. S. I know that I can use ToRadicals but my question is about the options Cubics and Quartics that seem do not have any effect for Eigenvalues.

• What version are you on? Eigenvalues[{{a, b, c}, {d, e, f}, {g, h, i}}, Cubics -> True] yields explicit radicals in 11.2. – J. M.'s technical difficulties Nov 1 '17 at 9:37
• I'm using version 11.2 on Linux x86 – Giancarlo Nov 1 '17 at 9:39
• Weird. It happens on a 32-bit kernel but not 64. I'll report it as a bug. – Daniel Lichtblau Nov 1 '17 at 15:36
• Works on Raspberry Pi too (v11.0.1, 32-bit, ARM) – Szabolcs Nov 2 '17 at 8:13