I am trying to find the Maximum of the following function with respect to variable b1. I use Mathematica to find the derivative and set it equal to zero. but its derivative w.r.t b1 is very complicated and I cannot get b1. (even I am not sure this function is concave?) I really appreciate if you could help me.
All my parameters in the model (b1,b2,B,v,w1,w2,D1,D2,q1,q2) are positive.
$[\frac{b1(B-b1)v}{1-b1w1-(B-b1)w2+b1(B-b1)v}e^{((-q1/b1)-(q2/(B-b1)))}]*[(D1.e^{(q1/b1)}-1).(D2.e^{(q2/(B-b1))}-1)]$