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tonykart44
Group Title
Hi everyone,
I'm currently studying for my calculus test tommorow and I have some problems which I have no clue how to solve.
1) Lim (cos 2x)^(csc^2 2x)
x> 0
Any help at all is very much appreciated, as I truly have no idea how to get started this excercise.
I'm sorry for not saying this earlier but L'Hopitals rule is not allowed.
 2 years ago
 2 years ago
tonykart44 Group Title
Hi everyone, I'm currently studying for my calculus test tommorow and I have some problems which I have no clue how to solve. 1) Lim (cos 2x)^(csc^2 2x) x> 0 Any help at all is very much appreciated, as I truly have no idea how to get started this excercise. I'm sorry for not saying this earlier but L'Hopitals rule is not allowed.
 2 years ago
 2 years ago

This Question is Open

satellite73 Group TitleBest ResponseYou've already chosen the best response.2
this looks like \(1^{\infty}\) so you can use l'hopital after you take the log
 2 years ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.2
when you see an exponential function like this, you usually have to take the log first and work with that one either that, or rewrite as \[e^{\csc^2(2x)\ln(\cos(2x)}\]
 2 years ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.2
i would take the log, get \[\csc^2(2x)\ln(\cos(2x))\] then rewrite as \[\frac{\ln(\cos(2x))}{\sin^2(2x)}\] to put it in the form \(\frac{0}{0}\) now you can use l'hopital
 2 years ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.2
when you get your answer to this, make sure to remember to raise \(e\) to that power, as you took the log as the first step
 2 years ago

tonykart44 Group TitleBest ResponseYou've already chosen the best response.0
Thank you very much for your fast answer but unfortunately we are not allowed to use L'Hoptials rule yet. I'm sorry I didn't specify that, is there another way to solve this problem?
 2 years ago

rahul91 Group TitleBest ResponseYou've already chosen the best response.0
i dont know whether it help take the whole expression = y and take log on both sides try to simplify
 2 years ago

tonykart44 Group TitleBest ResponseYou've already chosen the best response.0
That looks like it could work. I'll try that.
 2 years ago

tonykart44 Group TitleBest ResponseYou've already chosen the best response.0
But isn't that for solving derivatives?
 2 years ago

tonykart44 Group TitleBest ResponseYou've already chosen the best response.0
Ok so I got this one in the form (12sin^2 x)^(1/2sin^2 2x) but i don't know how to go on from there. I know i'm almost there but i don't know how to get rid of the 2x above, I know it's silly, but i just don't see it.
 2 years ago

rahul91 Group TitleBest ResponseYou've already chosen the best response.0
12sin^2x = cos2x
 2 years ago
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