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

$(log_5cos7x)'=frac{-7sin7x}{cos7xcdot ln5}=-frac{7}{ln5}cdot tg7x$