y=1/log(cos x)
dy/dx=?
answer in book is= tan x/[log(cos x)]^2
i took 1= ln e and then lnA/lnB=ln (A-B)
then chain rule i cant convert my anwer to the one given, am i right? or i made a mistake?

Question

y=1/log(cos x)
dy/dx=?
answer in book is= tan x/[log(cos x)]^2
i took 1= ln e and then lnA/lnB=ln (A-B)
then chain rule i cant convert my anwer to the one given, am i right? or i made a mistake?

anonymous · Answer

What's the base of your log 10?

yash2651995 · Answer

nah.. e ie Euler's number

anonymous · Answer

why don't you use the change of base formula?

yash2651995 · Answer

it is log to base e every where.. even in question it is log to base e

anonymous · Answer

That is fine but $$\log_a x= lnx/lna$$

anonymous · Answer

SO that you have $$\ln(cosx)/lne$$
and $$lne$$ is just 1

anonymous · Answer

$$y= 1/\ln(cosx)$$

anonymous · Answer

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