f ( a W ) = 2 + a W ( 1 − a W ) 3 2 ⋅ ( 0 , 76 + 4 , 8 ( a W ) − 11 , 58 ( a W ) 2 + 12 , 43 ( a W ) 3 − 4 , 08 ( a W ) 4 ) {\displaystyle f\left({\frac {a}{W}}\right)={\frac {2+{\frac {a}{W}}}{\left(1-{\frac {a}{W}}\right)^{\frac {3}{2}}}}\cdot \left(0,76+4,8\left({\frac {a}{W}}\right)-11,58\left({\frac {a}{W}}\right)^{2}+12,43\left({\frac {a}{W}}\right)^{3}-4,08\left({\frac {a}{W}}\right)^{4}\right)}
