Find the derivative of:
f(x) = 1/(3x)^4 + 3x^4
Determine the points, if any, at which the function has a horizontal tangent line
y = 5x^3 - 15x^2
y = 2x^3 + 6x^2
thank you!
f(x) = (3x)^-4 + 3x^4
f' = -4(3x)^-5(3) + 12x^2
= -12/(3x)^5 + 12x^2
where is 15x^2-30x = 0?
where is 6x^2+12x = 0?