Calculate the value of R2 required to deliver 5W to RL if Vin equals 5V.
The Attempt at a Solution
I started by using KVL for the input loop, noting that current is going counter-clockwise:
Input loop: iR2-Vin=0→R2=Vin/i
I found i by using P=Ri^2:
Then, I used i from above to solve for R2:
The answer should be 23.1Ω according to the book (Engineering Circuit Analysis 8ed). Where did I go wrong? I have tried so many different approaches, but I can never get to the answer of 23.1Ω.