How would you determine what sort of stationary point this curve has? x^3 - 6x^2 + 9x - 4

I would differentiate it and then turn it into an equation to find the points where the gradient equals zero. With these points at hand, I would take a second derivative, this tells me how the gradient changes with x and from this I would plug in my known points to see what value pops out. If it's postive I know that this stationary point is a minimum and if it's negative I know that this stationary point is a maximum. If the answer is zero then this hints at (but doesnt al+ways mean) a point of inflection. dy/dx = 3x2 - 12x + 9 3x2 -12x + 9 = 0 x2 - 4x + 3 = 0 (Dividing both sides with 3) (x - 3)(x-1) = 0, x=3 and x=1. d2y/dx2 = 6x -12 When x = 1, d2y/dx2 = -6 therefore a maximum When x = 3, d2y/dx2 = 6 therefore a minimum.

WM

Related Maths A Level answers

All answers ▸

Find the shortest distance between the line L: x=1+t, y=1+2t, z=1-t and the point A: (2,3,4)


Differentiate y=x/sin(x)


1. A small stone is dropped from a height of 25 meters above the ground. i) Find the time taken for the stone to reach the ground ii) Find the speed of the stone as it reaches the ground


Show by induction that sum_n(r*3^(r-1))=1/4+(3^n/4)*(2n-1) for n>0