1. The problem statement, all variables and given/known data http://img806.imageshack.us/img806/9455/67043570.jpg [Broken] 3. The attempt at a solution http://img443.imageshack.us/img443/2449/50431877.jpg [Broken] The part I got confused at was during the substitution. I understand that there is a bound change (1,9) because we just sub in the values of y (0, 4) into t. What I got confused about was what happened to the y^(1/2) in dt. To be honest, I've not encountered a problem like this before, usually when making the substitution I've only ever had to get rid of constants hanging around. Also, pointers to any other problems like this would be very helpful!