Can someone explain indepth how to get the solution to this question.
Show that the equation (x^4)+4x+c=0 has at most two real roots.
please and thanks.
Use Demoivre's sign change theorem. If c<0 then there is one sign change and if you sub -x for x you get one sign change...so if c<0 you have one positive real root and one negative...if c>0 you only have one real negative root