Question

Найти производную log_{5}cos7x

Answer 1

$y'=(log_5cos7x)'= \frac{1}{cos7x*ln5}*(cos7x)'= \frac{1}{cos7x*ln5}*(-sin7x)*(7x)'= \\ = \frac{-7sin7x}{ln5cos7x}$

Answer 2

$(log_5cos7x)'=\frac{-7sin7x}{cos7x\cdot ln5}=-\frac{7}{ln5}\cdot tg7x$