>>3

(20/9)^3 = 8000/81 < 11 < 100/9 = (10/3)^2,
3 {1+log(2)-2log(3)} < log(11) < 2 {1-log(3)},
これに数値を入れて
3 * 0.346787486 < log(11) < 2 * 0.522878745
1.04036246 < log(11) < 1.04575749

なお　log(11) ≒ 1.041392685