Log mean area ‘A’ of cylinder can be given as
1
\(\frac{{\log A_2 - \log A_1}}{{A_2 - A_1}}\)
2
\(\frac{{A_2 - A_1}}{{\log \left( {\frac{{A_2}}{{A_1}}} \right)}}\)
3
\(\frac{{\log A_2 - \log A_1}}{{\log \left( {\frac{{A_2}}{{A_1}}} \right)}}\)
4
None