![& [ b= rac{3 f^{2}}{3 f-f}= rac{3 f}{2}, quad rac{1}{a{1}}- rac{1}{b{1}}=- rac{1}{f{1}}, quad b{1}= rac{a{1} f{1}}{a{1}+f{1}} ] \ hline & [ b{1}= rac{3 f f{1}}{f_{1}+3 f} cdot(underbrace{ ext { Ombem }} egin{array}{l} ext { 1) } Phi_{1}=-0,94 ext { дптр;](/public/images/library/external/library-detail-hero-book.png)
Условие:
| Дано | Решение |
|---|---|
| $ \begin{array}{l} n=1,5 | |
| \Phi=4 \text { дптр } | |
| n{1}=1,7 \end{array} $ | $ \Phi=\frac{1}{f}=(n-1) \frac{2}{R}, \quad R=\frac{2(n-1)}{\Phi}, \quad f=\frac{1}{\Phi}, $ |
| a=a{1}=3 f | $ \Phi{1}=\left(\frac{n}{n{1}}-1\right) \frac{2}{R}, \quad f{1}=\frac{1}{\Phi{1}}, \frac{1}{a}+\frac{1}{b}=\frac{1}{f}, b=\frac{a f}{a-f} $ |
| 1) \Phi{1}- ? | |
| 2) f{1}- ? | |
| 3) b- ? |
b=\frac{3 f^{2}}{3 f-f}=\frac{3 f}{2}, \quad \frac{1}{a{1}}-\frac{1}{b{1}}=-\frac{1}{f{1}}, \quad b{1}=\frac{a{1} f{1}}{a{1}+f{1}}
$ \\
\hline & $
b{1}=\frac{3 f f{1}}{f_{1}+3 f} \cdot(\underbrace{\text { Ombem }} \begin{array}{l}
\text { 1) } \Phi_{1}=-0,94 \text { дптр; } \\
\text { 2) } f_{1}=-1,06 \mathrm{~m}
\end{array}
$ \\
\hline
\end{tabular}
3) $b=37,5 \mathrm{~cm}, \quad b_{1}=44 \mathrm{~cm}$.
$396\rangle$