Sprendimas: vLDenQ - 1
+ =
+ = $$\frac{1}{d}+\frac{1}{f}$$ = $$\frac{1}{F}$$ 
= + $$\frac{1}{F}$$ = $$\frac{1}{d}+\frac{1}{f}$$ 
F = $$F$$ = $$\frac{1}{\frac{1}{d}+\frac{1}{f}}$$ 
F = $$F$$ = $$\frac{1}{\frac{1}{0.21}+\frac{1}{0.28}}$$ 
F = $$F$$ = $$\frac{1}{\frac{1}{0.21}+\frac{25}{7}}$$ 
F = $$F$$ = $$\frac{1}{\frac{1225}{147}}$$ 
F = $$F$$ = $$\frac{1\cdot 3}{25}$$ 
F = $$F$$ = $$\frac{3}{25}$$ 
F = 0.12$$F$$ = $$0.12$$
