I second the challenge. The original solution does not take into avvount thedirection of the 1mA input current. Since Vi is -1V, and the voltage at the terminals of theop-amp is 0V then the input current direction will be towards thevoltage source, not towards the op-amp. Applying the -1V input voltage causes 1mA of current to bedrawn from the op-amp output through the 10k then through the 1kthen into the voltage source. This seems to be very difficult to see since the solutionmanual to the text also has this incorrect analysis. I second the challenge. The original solution does not take into avvount thedirection of the 1mA input current. Since Vi is -1V, and the voltage at the terminals of theop-amp is 0V then the input current direction will be towards thevoltage source, not towards the op-amp. Applying the -1V input voltage causes 1mA of current to bedrawn from the op-amp output through the 10k then through the 1kthen into the voltage source. This seems to be very difficult to see since the solutionmanual to the text also has this incorrect analysis.