You can use GeoGebra to find the inflection points of a function, and the tangent at a given inflection point:
GeoGebra Instruction 1
Algebra View and Graphics View under View in Menu. Algebra View and press Enter. InflectionPoint(<Polynomial>) in Algebra View. For <Polynomial>, enter the name of your function, then press Enter. The coordinates of the inflection points will appear in Algebra View. Tangents Algebra View. Note! GeoGebra will only find the inflection points of polynomial functions.