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<math>{B\Rightarrow  \begin{cases}  

<math>{B\Rightarrow  \begin{cases}  

C: \tau_{BC}^{\alpha}\times \eta_{BC}^{\beta}=0.3^1+{(1/5)}^2=0.012\\  

C: \tau_{BC}^{\alpha}\times \eta_{BC}^{\beta}=0.3^1\times {(1/5)}^2=0.012\\  

D: \tau_{BD}^{\alpha}\times \eta_{BD}^{\beta}=0.3^1+{(1/4)}^2=0.019

D: \tau_{BD}^{\alpha}\times \eta_{BD}^{\beta}=0.3^1 \times {(1/4)}^2=0.019

\end{cases}} </math>

\end{cases}} </math>

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