What are the points of inflection of #f(x)=x^6 + 3x^5 - x^4 - 40x^3 - 60x^2 + 8x + 5 #?
1 Answer
Jan 12, 2017
Explanation:
The first graph is for f and the second is for f''.
The second pinpoints zeros of f'', for points of inflexion (POI)
It is evident that the tangent crosses the curve near
Using these as starters for Newton-Raphson iteration,
the two POI are
.graph{x^6+3x^5-x^4-40x^3-60x^2 [-50, 50, -2000, 2000]}
graph{30x^4+60x^3-12x^2-240x-120 [-2.5, 2.5, -1.25, 1.25]}