I need to build this model:
We consider a population of female salmon, they live 4 years. Survival for first three years respectively: 0.5%,7%,15%. Each salmon has female kids only in 4 year and produces 5000 female offspring

Hello. I have a problem with DEplot and I hope someone could help me with this:

How I can solve this:

 
for different fⁿ(x₀) ? for f(x)=exp(x^2(a-x))

How to show what class of bifurcation is in this function :   exp(x²*(a-x)) ?

How I can solve it ? If I want a solution dependent of a. With fsolve? But how?

-x³+ax²-lnx=0