1/(2*3.14*2)*ln(2*(0.5/(219+2*42))+sqrt((4*0.25)/(219+2*45)^2) ) *((219+2*42)/219) Почему выходит с минусом ?
You are getting a negative number because you have an unmatched parenthesis. Probably whatever you use to do the computation computes the argument of the natural log (ln) as a number smaller than 1 (<1) and thereby gives you a negative number.
