Given expression $=\frac{2({\sin }^{2}63\mathrm{º}+{\sin }^{2}27\mathrm{º})+1}{2({\cos }^{2}17\mathrm{º}+{\cos }^{2}73\mathrm{º})-2}=\frac{2({\sin }^{2}63\mathrm{º}+{\cos }^{2}63\mathrm{º})+1}{3({\cos }^{2}17\mathrm{º}+{\sin }^{2}17\mathrm{º})-2}$

                $=\frac{(2\times 1)+1}{(3\times 1)-2}=\frac{3}{1}=3\left|\begin{array}{l}\because \sin 27\mathrm{º}=\sin (90\mathrm{º}-63\mathrm{º})=\cos 63\mathrm{º}\\ \cos 73\mathrm{º}=\cos (90\mathrm{º}-17\mathrm{º})=\sin 17\mathrm{º}\end{array}\right|$