Question 632109
{{{cot45=1/tan45=1/1=1}}}, {{{sec60=1/cos60=1/(1/2)=2}}},
{{{sin30=1/2}}}
{{{5 (cot45)^2  - (sec60)^2 + sin^2(30) =5*1^2-2^2+(1/2)^2=5-4+1/4=5/4}}}