Question: Need help solving rootof structure under given boundary conditions (to find C1,C4,C6 and C8)

Hello I am hoping someone can help me find a solution to this equation with MAPLE. The solution (sol) comes out as a rootof structure with constants numbered C1 to C8 (see input below,try yourself and see format of sol). I don't know how to simplify this rootof structure and find the values for the constants that i want. I know that C2=C3=C5=C7=0 but I need to find C1, C4, C6 and C8. Can anyone help me find the values for these constants when the boundary conditions are such that f1(0)=f2(0)=f3(0)=0 and f4(0)=(r1+r2+r3+r4)/r4 . Thank you very much. > restart; Digits := 10; > t := .335; > r1 := .47066796; > r2 := .791898; > r3 := 1.12193314; > r4 := 1.45162704; > b1 := r1/r2; > b2 := r2/r3; > b3 := r3/r4; > sys := {diff(f1(x), x, x)-f1(x)+f2(x) = 0, diff(f2(x), x, x)-f2(x)+f3(x)+b1*(f1(x)-f2(x)) = 0, diff(f4(x), x, x)+b3*(f3(x)-f4(x)) = 0, diff(f3(x), x, x)-f3(x)+f4(x)+b2*(f2(x)-f3(x)) = 0}; > sol := dsolve(sys, [f1, f2, f3, f4])
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