Question

lim(1-cosx)/x2 x趋向于0

Answer 1

0/0型求导
limf/g=limf'/g'
lim(1-cosx)/x2 =lim(1-cosx)'/(x^2 )'
=lim(sinx)/2x
=lim(sinx)'/(2x)'
=lim(cosx/2)
=1/2