Derivar función segunda y graficar?

<img src="https://tex.z-dn.net/?f=%5Ctextbf%7BEjercicio%3A%20%7D%5Ctext%7B%20Graficar%20la%20siguiente%20funci%5C%27on%20%7Df%28x%29%3Dx%5E2-x-2%5C%5C%20%5C%5C%0A%5Ctextbf%7BDesarrollo%7D%5C%5C%20%5C%5C%0A1.%5Ctexttt%7B%20Primero%20hallemos%20los%20puntos%20extremos%20%28si%20es%20que%20los%7D%5C%5C%0A%5Ctexttt%7B%20tiene%29%7D%5C%5C%20%5C%5C%0A%5Cclubsuit%5Ctextit%7B%20Criterio%20de%20la%20primera%20derivada%7D%5C%5C%20%5C%5C%0Af%27%28x%29%3D2x-1%5C%5C%20%5C%5C%0A%5Ctexttt%7Bigualamos%20a%20cero%20para%20hallar%20el%20punto%20cr%5C%27itico%7D%5C%5C%20%5C%5C%0A2x-1%3D0%5Cto%20%5Cboxed%7Bx%3D%5Cfrac%7B1%7D%7B2%7D%7D" />

<img src="https://tex.z-dn.net/?f=%5Cclubsuit%5Ctextit%7B%20Ahora%20verifiquemos%20si%20es%20un%20extremo%7D%5C%5C%20%5C%5C%0A%5Cbullet%5Ctexttt%7B%20Cuando%20%7Dx%5Cin%20%5Cleft%28-%5Cinfty%2C%5Cfrac%7B1%7D%7B2%7D%5Cright%29%5Ctexttt%7B%20se%20tiene%20%7D%20f%27%28x%29%5C%20%5Ctextless%20%5C%200~~~~~%20%28f%20%5Ctexttt%7B%20decrece%7D%29%5C%5C%20%5C%5C%20%5C%5C%0A%5Cbullet%5Ctexttt%7B%20Cuando%20%7Dx%5Cin%20%5Cleft%28%5Cfrac%7B1%7D%7B2%7D%2C%2B%5Cinfty%5Cright%29%5Ctexttt%7B%20se%20tiene%20%7D%20f%27%28x%29%5C%20%5Ctextgreater%20%5C%200~~~~~%20%28f%20%5Ctexttt%7B%20crece%7D%29%5C%5C%20%5C%5C%20%5C%5C%0A%5Ctexttt%7BPor%20lo%20tanto%20%7Dx%3D%5Cfrac%7B1%7D%7B2%7D%5Ctexttt%7B%20es%20un%20punto%20de%20m%5C%27inimo%20%7D" /> <img src="https://tex.z-dn.net/?f=%5Csphericalangle%5Ctextit%7B%20Observaci%5C%27on%3A%20%7D%5Ctexttt%7B%20Cuando%20calculamos%20los%20puntos%20cr%5C%27iticos%20%7D%5C%5C%20%0A%5Ctexttt%7Bmediante%20el%20criterio%20de%20la%20primera%20derivada%20estos%20pueden%7D%5C%5C%20%0A%5Ctexttt%7Bpuntos%20de%20extremos%20relativos%2C%20hasta%20que%20no%20se%20demuestre%7D%5C%5C%0A%5Ctexttt%7Bque%20son%20absolutos%2C%20o%20inclusive%20no%20sean%20extremos%20sino%20de%7D%5C%5C%0A%5Ctexttt%7Binflexi%5C%27on%20%7D%28%5Ctexttt%7Bcomo%20en%20el%20caso%20de%20la%20funci%5C%27on%20%7Df%28x%29%3Dx%5E3%29%5Ctexttt%7B%2C%20el%20cero%20%7D%5C%5C%5Ctexttt%7Bno%20es%20un%20extremo%2C%20mas%20es%20un%20punto%20de%20inflexi%5C%27on.%7D" />

<img src="https://tex.z-dn.net/?f=2.%5Ctextit%7B%20Puntos%20de%20inflexi%5C%27on%7D%5C%5C%20%5Cclubsuit%5Ctextit%7BCriterio%20de%20la%20segunda%20derivada%7D%5C%5C%20%5C%5C%0Af%27%27%28x%29%3D2%5C%5C%20%5C%5C%0A%5Ctexttt%7BEn%20este%20caso%20%7Df%27%27%5Cneq0%5Ctexttt%7B%20lo%20que%20significa%20que%20no%20hay%20punto%20de%20%7D%5C%5C%0A%5Ctexttt%7Bde%20inflexi%5C%27on%2C%20adem%5C%27as%20%7Df%27%27%5C%20%5Ctextgreater%20%5C%200%5Ctexttt%7B%20es%20decir%20que%20la%20gr%5C%27afica%20de%20%7Df%5C%5C%0A%5Ctexttt%7Bse%20abre%20hacia%20arriba%7D" />

<img src="https://tex.z-dn.net/?f=%5Ctextbf%7BResumen%7D%5C%5C%20%5C%5C%0A%5Chspace%2A%7B2cm%7D%5Cbegin%7Barray%7D%7B%7Cc%7C%7Cc%7Cc%7Cc%7C%7D%0A%5Ccline%7B1-3%7D%26%26%5C%5C%0A%5Ctext%7BIntervalos%7D%26%5Cleft%28-%5Cinfty%2C%5Cfrac%7B1%7D%7B2%7D%5Cright%29%26%5Cleft%28%5Cfrac%7B1%7D%7B2%7D%2C%2B%5Cinfty%5Cright%29%5C%5C%26%26%5C%5C%0A%5Ccline%7B1-3%7D%26%26%5C%5C%0A%5Ctext%7BMonoton%5C%27ia%7D%26%5Csearrow%26%5Cnearrow%5C%5C%20%26%26%5C%5C%0A%5Ccline%7B1-3%7D%26%26%5C%5C%0A%5Ctext%7BConcavidad%7D%26%5Csmile%26%5Csmile%5C%5C%26%26%5C%5C%0A%5Ccline%7B1-3%7D%0A%5Cend%7Barray%7D" />

La gráfica abajo.