Đáp án:
a) 0,025
b) -0,035
c) -0,015
Giải thích các bước giải:
\(\begin{array}{l}
a)D = (n - 1)(\dfrac{1}{{{R_1}}} + \dfrac{1}{{{R_2}}}) = (1,5 - 1)(\dfrac{1}{{20}} + \dfrac{1}{\infty }) = 0,025\\
b)D = (n - 1)(\dfrac{1}{{{R_1}}} + \dfrac{1}{{{R_2}}}) = (1,5 - 1)( - \dfrac{1}{{20}} - \dfrac{1}{{50}}) = - 0,035\\
c)D = (n - 1)(\dfrac{1}{{{R_1}}} + \dfrac{1}{{{R_2}}}) = (1,5 - 1)(\dfrac{1}{{50}} - \dfrac{1}{{20}}) = - 0,015
\end{array}\)
