1
$\begingroup$

I want to solve two inequations to find a variable range but Mathematica starts running but doesn't show any results after a long time.

First one should be NPV,s,Sale < NPV,s,Service. It will show us the r_min: enter image description here

First one should be NPV,c,Service < NPV,c,Sale. It will show us the r_max:

enter image description here

there is no other equation or inequation.

I used this code in Mathematica but I didn't get any results.

enter image description here

Solve[(1 - Ss)*(P - A) < (1 - Ss)*Sum[r/qs^t, {t, 1, T}] - A + 
     Ss*Sum[(bs*A)/qs^t, {t, 1, T}] + (1 - Ss)*Rt*(qs^(-T)) && 
   -P + Sc*Sum[(bc*P)/qc^t, {t, 1, T}] + ((1 - Sc)*Rt)/qc^T > 
    (-(1 - Sc))*Sum[r/qc^t, {t, 1, T}], r]
$\endgroup$
2
$\begingroup$

Factor the r from the Sum's and replace each sum with a constant:

res1=Reduce[(1 - Ss)*(P - A) < (1 - Ss)*r s1 - A + 
    Ss*s2 + (1 - Ss)*Rt*(qs^(-T)) && -P + 
    Sc*s3 + ((1 - Sc)*Rt)/qc^T > (-(1 - Sc))*r s4, r]

this produces an enormous conditional expression. You can try to simplify by adding appropriate assumptions on the symbols, eg,

Simplify[res1,Assumptions->{Element[{A, P, qc, qs, r, Rt, s1, s2, s3, s4, Sc, Ss, T},Reals],A>0}]

this is taking a long time, but if you know more appropriate assumptions to add on your constants it may help.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.