Question

find in which interval the function is strictly increasing and decreasing f(x)=1/4x⁴+2/3x³-5/2x²-6x+9
please explain it properly
please​

Answer 1

f(x) = 3x^4 - 4x^3 - 12x^2 + 5 f'(x) = 12x^3 - 12x^2 - 24x = 12x(x^2 - x - 2) f'(x) = 12x(x - 2)(x + 1) Put f'(x) = 0 x = 0, - 1, 2 Intervals are ( - ∞,