Розрахунок: SZ2A4D - 1

1

/ d

-

1

/ f

=
-

2

/ R

1

/ d

-

1

/ f

= -

2

/ R

$\frac{1}{d}-\frac{1}{f}$ = $-\frac{2}{R}$

1

/ d

= -

2

/ R

+

1

/ f

$\frac{1}{d}$ = $-\frac{2}{R}+\frac{1}{f}$

d =

1

/ (-

2

/ R

+

1

/ f

)

$d$ = $\frac{1}{-\frac{2}{R}+\frac{1}{f}}$