maxima and minima question

• Oct 4th 2008, 11:50 PM
jvignacio
maxima and minima question
Find the local maxima and minima, and all the inflection points, of
y
= 9x^4 11x^3 + 3x^2 + 1

how would i start off by doing this question? thank u

• Oct 5th 2008, 12:00 AM
mr fantastic
Quote:

Originally Posted by jvignacio
Find the local maxima and minima, and all the inflection points, of

y
= 9x^4 11x^3 + 3x^2 + 1

how would i start off by doing this question? thank u

x-coordinates of local maxima and minima: Solve $\frac{dy}{dx} = 0$. Use the double derivative test (or the sign test) to determine the nature of the stationary points.

If you want NON-stationary points of inflection as well, solve $\frac{d^2y}{dx^2} = 0$. Points of inflection for y occur where $\frac{dy}{dx}$ has either a maximum or a minimum turning point.