Найди значения выражений и запиши ответы

1. \(\sin ^4\alpha+\sin ^2\alpha\cos ^2\alpha-\sin ^2\alpha=\) [ ].
2. \(\cos ^2(180\degree-60\degree)+\sin (180\degree-60\degree)\cos (90\degree-60\degree)=\) [ ].
3. \(\cos ^225\degree+\cos ^265\degree=\) [ ].