詳解：乘法微分公式

\(f'(x) = {\left( {{{\log }_7}x} \right)^\prime }\left( {{6^x}} \right) + \left( {{{\log }_7}x} \right){\left( {{6^x}} \right)^\prime }\)

\(f'(x) = \frac{1}{x} \cdot \frac{1}{{\ln 7}}\left( {{6^x}} \right) + \left( {{{\log }_7}x} \right){6^x}\ln 6\)