表达式5: "k" left parenthesis, "t" , right parenthesis equals StartFraction, StartAbsoluteValue, left parenthesis, "C" prime left parenthesis, "t" , right parenthesis times "C" prime prime left parenthesis, "t" , right parenthesis , right parenthesis , EndAbsoluteValue Over StartAbsoluteValue, "C" prime left parenthesis, "t" , right parenthesis , EndAbsoluteValue cubed , EndFractionkt=C′t×C′′tC′t3
5
表达式6: "T" left parenthesis, "t" , right parenthesis equals StartFraction, "C" prime left parenthesis, "t" , right parenthesis Over StartAbsoluteValue, "C" prime left parenthesis, "t" , right parenthesis , EndAbsoluteValue , EndFractionTt=C′tC′t
6
表达式7: "N" left parenthesis, "t" , right parenthesis equals StartFraction, "T" prime left parenthesis, "t" , right parenthesis Over StartAbsoluteValue, "T" prime left parenthesis, "t" , right parenthesis , EndAbsoluteValue , EndFractionNt=T′tT′t
