how to integrate zero to t e^(s^2) ds, if I know how to integrate this. I should be able to answer: show that y1=e^-(t^2)/2 and y2=e^-(t^2)/2 (integral) 0 to t e^(s^2)/2 form set of solutions to the differential equation y" + ty' + y = 0 , on the interval all real numbers. I would take derivative of the two equations and find its determinant. determinant !=0 they form a fundamental set of solutions