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system of equations

Posted 2 months ago
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Hi To solve the system :

x=1700/E^(y/15.5)
x=180/E^(y/93.3)

I was trying :

Solve[x==1700/E^(y/15.5)&&x==180/E^(y/93.3),{x,y}] 

How can I solve this system with Wolfram Language?

3 Replies
Posted 2 months ago

Here is some examples from my code :

ClearAll["Global`*"];
eq = Solve[
   masaTotal - 1/4*masaApa == 2050 && 
    masaTotal - 1/2*masaApa == 1450 && masaTotal - masaApa == masaVas,
   {masaTotal, masaApa, masaVas}, PositiveIntegers] // Flatten


ClearAll["Global`*"];
eq1 = 5*k1 - 4*k2 == 108;
eq2 = 5*k3 - 4*k4 == 0;
eq3 = 5*k5 - 4*k6 == 36*5;
eq4 = k1 + k2 == 36;
eq5 = k3 + k4 == 36;
eq6 = k5 + k6 == 36;
mySol = Solve[
   eq1 && eq2 && eq3 && eq5 && eq4 && eq6, {k1, k2, k3, k4, k5, k6}, 
   Reals] // Flatten

Modify them

Posted 2 months ago

Hi Luis,

Since both of the RHS equal x, there is no need for x.

Solve[Rationalize@{1700/E^(y/15.5) == 180/E^(y/93.3)}, y, Reals]
(* {{y -> -((28923 (2 Log[3] - Log[5] - Log[17]))/1556)}} *)

Use N to get the a numeric result

(* {{y -> 41.7381}} *)
Posted 2 months ago

If you are only interested in the Real solution then

FindRoot[x==1700/E^(y/15.5)&&x==180/E^(y/93.3),{{x,0},{y,0}}] 

instantly returns

{x->115.077,y->41.7381}
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