求二次导 f(x) = x^6*cosx

求二次导 f(x) = x^6*cosx

求二次导 f(x) = x^6*cosx

求二次导 f(x) = x^6*cosx
f'(x) = 6x⁵cosx - x⁶sinx
f"(x) = 30x⁴cosx - 6x⁵sinx - 6x⁵sinx - x⁶cosx
= -x⁶cosx - 12x⁵sinx + 30x⁴cosx