ouzhonghui
(Jacques Ou)
1
How to turn eq1 into eq2?
Thanks.
eq1 = (-A2 + pinf (s + \[Theta]c))/(s (s + \[Theta]c)) - (
A1 Dc E^((lh - x) Sqrt[(s + \[Theta]c)/
Dc]) (\[Alpha]1 Sqrt[Dp (s + \[Theta]c)] + Sqrt[
s (s + \[Theta]c)]))/((Sqrt[s] +
Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) (-Dc s +
Dp (s + \[Theta]c))) + (E^((s (lh - x))/Sqrt[
Dp s]) (Sqrt[
Dp] \[Alpha]1 (Dc s - Dp (s + \[Theta]c)) (-A2 +
pinf (s + \[Theta]c)) +
A1 s (Sqrt[Dc Dp] s + Sqrt[Dc Dp] \[Theta]c +
Dc \[Alpha]1 Sqrt[Dp (s + \[Theta]c)])))/(s (Sqrt[s] +
Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) (-Dc s +
Dp (s + \[Theta]c)))
eq2 = -((A1 Dc E^((lh - x) Sqrt[(s + \[Theta]c)/Dc]))/(
Sqrt[s + \[Theta]c] (-Dc s + Dp (s + \[Theta]c)))) + (-A2 +
pinf (s + \[Theta]c))/(s (s + \[Theta]c)) +
E^((s (lh - x))/Sqrt[
Dp s]) ((
A1 Sqrt[Dc Dp])/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) (-Dc s +
Dp (s + \[Theta]c))) + (
A1 Dc Sqrt[Dp] \[Alpha]1)/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp (s + \[Theta]c))) - (
Sqrt[Dp] \[Alpha]1 (-A2 + pinf (s + \[Theta]c)))/(
s (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c)))
Collecting the exponential comes close to your form:
Collect[eq1, E^_, Simplify]
ouzhonghui
(Jacques Ou)
3
Dear Gianluca,
I tried ‘Collect’ and ‘Simplify’, but the fractions in the results are not the simplest.
In[66]:= eq3 = Collect[eq1, E^_, Simplify]
Out[66]= (-A2 + pinf (s + \[Theta]c))/(s (s + \[Theta]c)) - (
A1 Dc E^((lh - x) Sqrt[(s + \[Theta]c)/
Dc]) (\[Alpha]1 Sqrt[Dp (s + \[Theta]c)] + Sqrt[
s (s + \[Theta]c)]))/((Sqrt[s] +
Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) (-Dc s +
Dp (s + \[Theta]c))) + (E^((s (lh - x))/Sqrt[
Dp s]) (Sqrt[
Dp] \[Alpha]1 (Dc s - Dp (s + \[Theta]c)) (-A2 +
pinf (s + \[Theta]c)) +
A1 s (Sqrt[Dc Dp] s + Sqrt[Dc Dp] \[Theta]c +
Dc \[Alpha]1 Sqrt[Dp (s + \[Theta]c)])))/(s (Sqrt[s] +
Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) (-Dc s +
Dp (s + \[Theta]c)))
This is even simpler:
eq4 = -((A1 Dc E^((lh - x) Sqrt[(s + \[Theta]c)/Dc]))/(Sqrt[
s + \[Theta]c] (-Dc s + Dp (s + \[Theta]c)))) + (-A2 +
pinf (s + \[Theta]c))/(s (s + \[Theta]c)) +
E^((s (lh - x))/Sqrt[Dp s]) (
Sqrt[Dp] ((A1 Sqrt[Dc])/(-Dc s + Dp (s + \[Theta]c)) + (
A1 Dc \[Alpha]1)/(
Sqrt[s + \[Theta]c] (-Dc s +
Dp (s + \[Theta]c))) - (\[Alpha]1 (-A2 +
pinf (s + \[Theta]c)))/(s (s + \[Theta]c))))/(
Sqrt[s] + Sqrt[Dp] \[Alpha]1)
ouzhonghui
(Jacques Ou)
5
Dear Gianluca,
Would you like to tell me how to get the result above?
Thanks.