After two years it is 5 meters tall. If we find out how much it grew, we can figure out how tall it was at transplantation. This is just the integral from 0 to 2 of (1+1/(x+1)^2). Performing the definite integral yields x-1/(1+x) . Evaluating between 0 and 2 yields 5/3-(-1)=8/3. Thus the tree has grown 8/3 meters, and was originally 5-8/3=(15-8)/3=7/3 meters.