6*[sqrt(2)-(cosx+sinx)]*[sqrt(2)+(cosx+sinx)] / { [1-sin2x]* [sqrt(2)+(cosx+sinx)] }=6*[2-(cosx+sinx)^2] / { [1-sin2x]* [2sqrt(2)] }=
6*[2-(1+2sinxcosx)] / { [1-sin2x]* [2sqrt(2)] }=6*[2-(1+sin2x)] / { [1-sin2x]* [2sqrt(2)] }=6*[1+sin2x] / { [1-sin2x]* [2sqrt(2)] }=6/[2sqrt(2)]=3/sqrt(2)=3sqrt(2)/2