Odpowiedź:
d)
Szczegółowe wyjaśnienie:
[tex]sin72^{0} = sin(90^{0}-18^{0})=cos18^{0} \ \ \rightarrow \ \ sin^{2}72^{0} = cos^{2}18^{0}\\oraz\\sin^{2}\alpha + cos^{2}\alpha = 1[/tex]
[tex]4sin^{2}18^{0}+3sn^{2}72^{0} + cos^{2}18^{0}=\\\\=4sin^{2}18^{0}+3sin^{2}(90^{0}-18^{0})+cos^{2}18^{0}=\\\\=4sin^{2}18^{0}+3cos^{2}18^{0}+cos^{2}18^{0}=\\\\=4sin^{2}18^{0}+4cos^{2}18^{0}=\\\\=4(sin^{2}18^{0}+cos^{2}18^{0})=\\\\=4\cdot1 = 4[/tex]
