y = log_2 (x^3 - tg 6x)
y = ln (x^3 - tg 6x)/ln 2
Тогда
y' = (ln (x^3 - tg 6x)/ln 2)' = 1/ln 2 * (ln (x^3 - tg 6x))' = 1/ln 2 * 1/(x^3 - tg 6x) * (x^3 - tg 6x)' =
= 1/ln 2 * 1/(x^3 - tg 6x) * (3x^2 - 6/(cos 6x)^2).