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Differentiable function q

I can't even do 1i. I first considered when x_0 is real but never equal to 1. Then I considered the limit of differentiable function definition. But this is a very dirty limit, my guess is that it doesn't exist but how would I prove this?

I am aware that u can check the lh limit and rh limit then conclude they are different but this limit is too dirty.

Posted from TSR Mobile
(edited 9 years ago)
This is what I have now. Im guessing it is missing so much justification but is this on the right lines?

Posted from TSR Mobile
Original post by cooldudeman
This is what I have now. Im guessing it is missing so much justification but is this on the right lines?No. Looks like you've completely forgotten what a limit is, to be honest.
Original post by DFranklin
No. Looks like you've completely forgotten what a limit is, to be honest.


Can you start me off please

Posted from TSR Mobile
Original post by cooldudeman
Can you start me off please

Posted from TSR Mobile


In the second post you posted, can you explain why the 3rd line is ++\infty? I don't imagine it is.
Original post by TheIrrational
In the second post you posted, can you explain why the 3rd line is ++\infty? I don't imagine it is.


well I really don't know what to do with the top part of the fraction and the h is gonna approach 0 from the right so its going to be positive.
I don't know what do at all tbh
Original post by DFranklin
No. Looks like you've completely forgotten what a limit is, to be honest.


I have redone the first question. Could you have a look please and tell me if I have done it correctly. I am a bit unsure on 1ii

Posted from TSR Mobile
Original post by cooldudeman
I have redone the first question. Could you have a look please and tell me if I have done it correctly. I am a bit unsure on 1iiMuch better, but limx1cos(1x1)\displaystyle \lim_{x \to 1} \cos\left(\dfrac{1}{x-1}\right) doesn't exist (and neither does the similar sin limit), so the line where you take those limits is incorrect.

Spoiler

Original post by DFranklin
Much better, but limx1cos(1x1)\displaystyle \lim_{x \to 1} \cos\left(\dfrac{1}{x-1}\right) doesn't exist (and neither does the similar sin limit), so the line where you take those limits is incorrect.

Spoiler



OK but after reading your spoiler, how are you supposed to phrase this last bit then? Since you said they don't have to exist.

Posted from TSR Mobile
Something like: "|cos(1/(x-1)| |x-1| <= |x-1|, the RHS->0 so by the squeeze thereom so does the LHS".

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