Odpowiedź :
[tex]sin^{4}\alpha-cos^{4}\alpha = (sn^{2}\alpha + cos^{2}\alpha)(sin^{2}\alpha - cos^{2}\alpha) = 1\cdot(sin^{2}\alpha-cos^{2}\alpha) =\\\\= sin^{2}\alpha - cos^{2}\alpha\\\\Odp. \ a)[/tex]
[tex]sin^{4}\alpha-cos^{4}\alpha = (sn^{2}\alpha + cos^{2}\alpha)(sin^{2}\alpha - cos^{2}\alpha) = 1\cdot(sin^{2}\alpha-cos^{2}\alpha) =\\\\= sin^{2}\alpha - cos^{2}\alpha\\\\Odp. \ a)[/tex]