This isnt really homework, its a problem im attempting

http://img405.imageshack.us/img405/9469/93511342nl4.jpg

IS THIS SOLUTION CORRECT?

for the first equation i get C_2 = Log((1-a)/(1+a)) I Do NOT see how they can get that answer

then this gives the solution for the second bit as

C_1 = ( log ((1+b)/(1-b) + log ((1-a)/(1+a)) )^-1

HELP PLEASE, thank you