Question 2 the limit of (1-cos(x))/(x^2) as x approaches 0. i applied l'Hospitals rule twice and came up with -1/2 my professor got positive 1/2 help me out.

-i know it has the form 0/0.

-after i applied LH rule the 1st time i got (0+1sinx)/(2x)

-LH applied twice i got (-cos(x))/(2) = -1/2

Also this problem has been troubling me is there a formula that could help me out? thanks everyone.