solve it quickly......

lets put h=(pie/2)-x

hence the expression will become

cot(pie/2-h)-cos(pie/2-h)/h^3

= tanh-sinh/h^3

= [sinh/cosh-sinh]/h^3 = = [sinh{(1/cosh)-1}]/h^3 = [sinh(1-cosh)]/(h^3)cosh

= [tanh x (1-cosh)]h^3 = limh going to 0 tanh/h x (1-cosh)/h^2

= 1x1/2=1/2

so i think ans should be 1/2

correct me if i am wrong or nudge me if you have any doubts