Approximate answer on integrals of exponential and power functions

An approximate solution for integrals of product of power function, exponential function with the inverted parabola of the second order argument, modified Bessel function of first kind and biased error function is received. In the course of evaluation a integrals of product of power and exponential functions are brought into a closed form and standard integrals of product of power and biased exponential functions are simplified. The result suggests desired number of members with the integral error not to be in excess of specified value. This paper presents the power series expansion of modified Bessel function of first kind and incomplete gamma function. Working results may be required in mechanical and radio engineering processes research.