I used the commands Assuming and /. to simplify the expression, but they didn't work. Would you like to have a look at this issue? Thanks.
In[122]:= eq1 = (
2 A1 Dc Sqrt[Dp] E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s)/(Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Sqrt[Dp]
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp^(3/2)
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s \[Alpha]1)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dc Sqrt[Dp] s)/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A2 Dp^(3/2) Sqrt[
s + \[Theta]c])/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Sqrt[Dc] Dp^(3/2)
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp]) s Sqrt[
s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A2 Dp^2 \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dp^2 E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp^(3/2) pinf s \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp pinf Sqrt[s] (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp^(3/2) pinf \[Alpha]1 (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf \[Alpha]1 Sqrt[Dp^3 s^5 (s + \[Theta]c)])/(
Sqrt[s] Sqrt[s/
Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf \[Alpha]1 \[Theta]c (2 s + \[Theta]c))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp Sqrt[
s] (-pinf s^2 + A2 Sqrt[Dp s] \[Alpha]1 - pinf s \[Theta]c))/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) (2 s^3 - Sqrt[Dp s^5] \[Alpha]1 + 2 s^2 \[Theta]c))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 (A2 s Sqrt[Dp s] Sqrt[s + \[Theta]c] -
pinf Sqrt[Dp s^5 (s + \[Theta]c)]))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c))
Out[122]= (
2 A1 Dc Sqrt[Dp]
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp]) s)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Sqrt[Dp]
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp^(3/2)
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s \[Alpha]1)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dc Sqrt[Dp] s)/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c]
Sqrt[Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + DpDp \[Theta]c)) - (
A2 Dp^(3/2) Sqrt[
s + \[Theta]c])/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Sqrt[Dc] Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s Sqrt[s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A2 Dp^2 \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dp^2 E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp^(3/2) pinf s \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp pinf Sqrt[s] (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp^(3/2) pinf \[Alpha]1 (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp]) pinf \[Alpha]1 Sqrt[
Dp^3 s^5 (s + \[Theta]c)])/(
Sqrt[s] Sqrt[s/
Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf \[Alpha]1 \[Theta]c (2 s + \[Theta]c))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp Sqrt[
s] (-pinf s^2 + A2 Sqrt[Dp s] \[Alpha]1 - pinf s \[Theta]c))/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) (2 s^3 - Sqrt[Dp s^5] \[Alpha]1 + 2 s^2 \[Theta]c))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 (A2 s Sqrt[Dp s] Sqrt[s + \[Theta]c] -
pinf Sqrt[Dp s^5 (s + \[Theta]c)]))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c))
In[123]:= eq2 =
Assuming[s > 0 && (s + \[Theta]c) > 0 && Dp > 0,
Cancel[eq1]] /. {Sqrt[Dp s] -> Sqrt[Dp] Sqrt[ s],
Sqrt[Dp s (s + \[Theta]c)] ->
Sqrt[Dp ] Sqrt[ s ] Sqrt[s + \[Theta]c],
Sqrt[s/Dp] -> Sqrt[s]/Sqrt[Dp]}
Out[123]= (
2 A1 Dc Sqrt[Dp]
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp]) s)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Sqrt[Dp]
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
s + \[Theta]c] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp^(3/2)
E^((lh Sqrt[s + \[Theta]c])/Sqrt[Dc] - (x Sqrt[s + \[Theta]c])/
Sqrt[Dc]) s \[Alpha]1)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dc Sqrt[Dp] s)/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c]
Sqrt[Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf s \[Alpha]1 \[Theta]c)/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A2 Dp^(3/2) Sqrt[
s + \[Theta]c])/((Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A1 Sqrt[Dc] Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
s Sqrt[s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A2 Dp^2 \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
A2 Dp^2 E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp^(3/2) pinf s \[Alpha]1 Sqrt[s + \[Theta]c])/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp pinf Sqrt[s] (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dp^(3/2) pinf \[Alpha]1 (s + \[Theta]c)^(3/2))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp]) pinf \[Alpha]1 Sqrt[
Dp^3 s^5 (s + \[Theta]c)])/(
Sqrt[s] Sqrt[s/
Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dp^(3/2) E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[Dp])
pinf \[Alpha]1 \[Theta]c (2 s + \[Theta]c))/(
Sqrt[s/Dp] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) + (
Dc Dp Sqrt[
s] (-pinf s^2 + A2 Sqrt[Dp] Sqrt[s] \[Alpha]1 - pinf s \[Theta]c))/(
Sqrt[Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) Sqrt[s + \[Theta]c] Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
A1 Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) (2 s^3 - Sqrt[Dp s^5] \[Alpha]1 + 2 s^2 \[Theta]c))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c)) - (
Dc Dp E^((lh Sqrt[s])/Sqrt[Dp] - (Sqrt[s] x)/Sqrt[
Dp]) \[Alpha]1 (A2 Sqrt[Dp] s^(3/2) Sqrt[s + \[Theta]c] -
pinf Sqrt[Dp s^5 (s + \[Theta]c)]))/(
Sqrt[s] Sqrt[
Dp s] (Sqrt[s] + Sqrt[Dp] \[Alpha]1) (s + \[Theta]c) Sqrt[
Dp s (s + \[Theta]c)] (-Dc s + Dp s + Dp \[Theta]c))