Question

Find lim 1-sec^2x over cosx-1, x->0.

Answer 1

maybe some algebra first, since this is like
\[\frac{1-\frac{1}{a^2}}{a-1}=\frac{a+1}{x^2}\] so you are starting with
\[\frac{\cos(x)+1}{\cos^2(x)}\]

Answer 2

replace x by 0 and you will get the answer

Answer 3

i get 2