Calculus - Derivative of tan and cot

[@andrei57792]

Hi can you please explain to me ?
How it's became 1/Cos2(x) + Sinx/CosX ?
at the part of 3:27 ?
How did you get that ?
From this part ?
Response please.
Thank you.

[@cyrusdavidpastelero2273]

It became 1/Cos2(x) + Sinx/CosX because sec^2(x)=1/cos^2(x) and tan(x)=sin(x)/cos(x)

[@andrei57792]

@@cyrusdavidpastelero2273 ahh ok thank you :)

[@jjm615]

The last one :sin x is not supposed to change to cos x?

[@yearofthevirgo]

Thanks

[@rvnsssmlakshmi1707]

If 3f (x)-2f (1/x)=x then f '(2)=
Please keep the answer for me please

[@yearofthevirgo]

Why did you put the sec^2x back into the equation?

[@Penzxi]

it is just simplified