`(1-sin^(2)30^(@))/(1+sin^(2)30^(@))xx(cos^(2)60^(@)+cos^(2)30^(@))/("cosec"^(2)90^(@)-cot^(2)90^(@)) divide (sin60^(@) tan30^(@))`

`=(1-((1)/(2))^(2))/(1+((1)/(2))^(2))xx (((1)/(2))^(2)+((sqrt(3))/(2))^(2))/((1)^(2)-0) divide ((sqrt(3))/(2) xx (1)/(sqrt(3)))`

`=(1-(1)/(4))/(1+(1)/(4)) xx ((1)/(4) +(3)/(4))/(1) divide (1)/(2) =((3)/(4))/((5)/(4))xx(1)/(1) divide (1)/(2)`

`=(3)/(4)xx(4)/(5) xx 1xx(2)/(1)=(6)/(5)=1(1)/(5)`.