# Equation of the average power delivered to the load

#### i_nour

Joined Nov 9, 2015
31
how do we get (Rth + Rl)^2 + (Xth + Xl)^2 in the denominator ?!

isn't (Zth+Zl)^2=(Rth+Rl)^2 + 2j (Rth+Rl)(Xth+Xl) - (Xth+Xl)^2 ?

#### WBahn

Joined Mar 31, 2012
26,398
The key is to note that

Z² is not the same as |Z|²

Try taking the magnitude of what you got and you will get their result, since

|Z²| = |Z|²