The International Journal of Applied Economics and Finance1991-08862077-2149Asian Network for Scientific Information10.3923/ijaef.2007.105.112α y^{β}]]>Seifedine Kadry Khaled Smaily 2200712In this research, our objective is to evaluate the probability density function of z = x^{α}y^{β}, where, x and y are two independent random variables, by using the probabilistic transformation method. The Probabilistic Transformation Methods (PTM) evaluate the Probability Density Function (PDF) of a function by multiplying the input pdf by the Jacobian of the inverse function. A new theorem for two input and one output has been developed. The result of our method is verified by the Monte Carlo simulation.]]>Champier, S.,2000Falsone, G. and N. Impollonia,2002Freund, J., I. Miller and R. Jhonson,2004Hogg, R. and A. Craig,1994Jimenez, J.C., I. Shoji and T. Ozaki,1999Kadry, S. and R. Younes,2005Sudret, B. et al.,2004Wojtkiewicz, S.F. and L.A. Bergman,2000