f(x)= -2x^3 + 5x^2 -3x +1
Is f(x) increasing or decreasing when x=-2???
I think its increasing?
also does the f ' (x) and f '' (x) tell you the same thing about cubic fuctions than quadratic functions?
I think the f ' (x) tells me the gradient of the tangent line and f''(x) tells if the turning point is max or min??
Thanks on another question
f(x)=x^2 -2x -8
it says use the first derivative to find exact turning point of f(x)
so f ' (x)= 2x-2
so x =1?? is this correct
so that means the turning point is (1,-8) and the other roots are (4,0) and (-2,0)?
its seems to cut the yintercept at -6? I thought by looking at the constant -8 it woul cut there..