Question

help
evaluate lim(cos(ax)-cos(bx))\(x squared),as x approach 0

Answer 1

Can I use l'hopital's rule?

Answer 2

tell me about it

Answer 3

lim x->a (f(x)/g(x))=lim x->a (f'(x)/g'(x))
l'hopital (sometimes l'hospital I think) can only be used for indeterminant forms of 0/0, plus minus infinity/0, plus minus infinity/plus minus infinity, and some additional cases which youc an google.