pickRationalBaseIntegerExponent()
VALS.base_n
VALS.base_d
VALS.exp < 0
EXP_NEG ? "-" : ""
abs( VALS.exp )
EXP_NEG ? BASE_D : BASE_N
EXP_NEG ? BASE_N : BASE_D
VALS.sol_n
VALS.sol_d
\Large fracParens( BASE_N, BASE_D )^{EXP_SIGN+EXP}
SOL_N / SOL_D
= fracParens( BASEF_N, BASEF_D )^{EXP}
= frac( SOL_N, SOL_D )