Gegeven: \eqalign{ & \frac{1} {f} = \frac{1} {v} + \frac{1} {b}}
- Druk f, v en b uit in de andere variabelen
Uitwerking
\eqalign{ & \frac{1} {f} = \frac{1} {v} + \frac{1} {b} \cr & \frac{1} {f} = \frac{b} {{vb}} + \frac{v} {{vb}} \cr & \frac{1} {f} = \frac{{b + v}} {{vb}} \cr & f = \frac{{vb}} {{b + v}} \cr}
\eqalign{ & \frac{1} {f} = \frac{1} {v} + \frac{1} {b} \cr & \frac{1} {v} = \frac{1} {f} - \frac{1} {b} \cr & \frac{1} {v} = \frac{b} {{bf}} - \frac{f} {{bf}} \cr & \frac{1} {v} = \frac{{b - f}} {{bf}} \cr & v = \frac{{bf}} {{b - f}} \cr}
\eqalign{ & \frac{1} {f} = \frac{1} {v} + \frac{1} {b} \cr & \frac{1} {b} = \frac{1} {f} - \frac{1} {v} \cr & \frac{1} {b} = \frac{v} {{fv}} - \frac{f} {{fv}} \cr & \frac{1} {b} = \frac{{v - f}} {{fv}} \cr & b = \frac{{fv}} {{v - f}} \cr}
