Derivative of sec(x) from first principles (definition) 

I don't know if I should call you bro or teacher, bt the truth is that you are undoubtedly amazing 💯

you're very strong sir, i enjoyed your courage and smiles when explaining the concepts, thank you very much (watching from Zambia)

i am from india i understood completely loved the video

Explain this better than my lecturer at University. Thank you, blessed.

Excellent presentation, sir. Very helpful and encouraging.

Watching from Pakistan 🇵🇰, you are such a helpful person for student who are studying calculas after completing intermediate in medical 😅,

You are the exact definition of simplicity 😮

very easy to understand. thank you for such a lovely video

i was so confused thank you so much I was about to cry about this problem but you solved it so easily! ahhhh thank you!!

i noticed something: by 3:06, instead of using identities, you can just factor out (1/h)(cos(x) - cos(x+h)), and notice that this is just definition of the derivative (almost... it's negative instead) of cos(x). So now you're left with -(-sin(x)) * lim_h->0 (1/cos(x)cos(x+h)) = sin(x) * sec^2(x) = sec(x)tan(x) Same can be done with the derivative of cosecant!

Nice video.

GOAT thanks for the video

you are my hero sir

I stumbled over a sign issue this helped me realise where I went wrong

youre the best💯💯💯💯

This one also! 🤩

Sir what happened on the sign issue?

😊😊😊

you are from which country

I wish to know if (1-cosx)/x =0 or (cosx -1)/x =0. I am asking because you use the first relation in this video and in the video of sinx, you used the second relation. I know that you just need to multiply the second equation by -1 to solve the problem but I wish to know exactly which is the right relation…. Thanks in advance….anyway, your videos are quite good

sorry me ! i had already done upto last 2nd line then tore my page thinking i got it worng . then searched for this vid and wow i really am stupid

what of 1/cosx

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