Question

using first derivative test find the local maxima and minima of the function f(x) =x³-12x

Answer 1

• f'(x)=3x²-12
• local maxima and minima lies at critical points
• 0=3(x²-4)
• 0=3(x-2)(x+2)
• so you get two values x=2 and x=-2
• for x=2 f(x)=-16     it pt of local maxima
• for x=-2 f(x)=-32   its pt of local minima