Calculation: dA1oCp - 1

p_avg  = 
 
 I_m^2* R
/ 2
p_avg =  
 I_m^2* R
/ 2
$$p_{avg}$$ = $$\frac{I_{m}^{2}\cdot R}{2}$$
p_avg =  0.5* I_m^2* R$$p_{avg}$$ = $$0.5\cdot I_{m}^{2}\cdot R$$