Bailey, Andrea, Danny, Riley, anabelle, holly, LILLY, zachary, I'm stumped -- or whoever!
Please post under one name. There's no reason to post under several.
here is the question:
determine the minimum gradient of the curve y=2^3 - 9x^2 + 5
when they say the minimum gradient, does that mean the minimum value of d^2y/dx^2?
how do i do this??
2 answers
They want the minimum value of dy/dx. That would be where the second derivative is zero, but you have to test that it isn't a maximum.
You seem to have mistyped the function, which probably should be
y(x) = 2x^3 -9x^2 +5
dy/dx = 6x^2 -18x
d^2y/dx^2 = 12x -18
That = 0 when x = 3/2
Since the third derivative is positive, x = 3/2 is a minimum gradient location
You seem to have mistyped the function, which probably should be
y(x) = 2x^3 -9x^2 +5
dy/dx = 6x^2 -18x
d^2y/dx^2 = 12x -18
That = 0 when x = 3/2
Since the third derivative is positive, x = 3/2 is a minimum gradient location
1 answer