Найти производную второго порядка функции y = f(x)

Y'=tg(6x-7)∙(3x3+4x2-2x+1)'=
=tg(6x-7)'∙3x3+4x2-2x+1+tg6x-7∙3x3+4x2-2x+1'=
=(6x-7)'cos2(6x-7)3x3+4x2-2x+1+tg6x-79x2+8x-2=
=6sec2(6x-7)∙3x3+4x2-2x+1+tg6x-7∙9x2+8x-2=
y''=6cos2(6x-7)∙3x3+4x2-2x+1+tg6x-7∙9x2+8x-2'=
=6cos2(6x-7)'∙3x3+4x2-2x+1+6cos26x-73x3+4x2-2x+1'+
+tg6x-7'∙9x2+8x-2+tg6x-7∙9x2+8x-2'=
=62∙cos6x-7∙sin6x-7cos46x-73x3+4x2-2x+1+6sec26x-79x2+8x-2+
+6cos26x-7∙9x2+8x-2+tg6x-7∙18x+8=
=723x3+4x2-2x+1∙tg6x-7∙sec26x-7+129x2+8x-2sec26x-7+
+tg6x-7∙18x+8.
Ответ:y'=723x3+4x2-2x+1∙tg6x-7∙sec26x-7+
+129x2+8x-2sec26x-7+tg6x-7∙18x+8.