Sa se arate ca:
a)[tex] \frac{cos12°+ \sqrt{3} sin12°}{cos3°-sin3°} = \sqrt{2} [/tex]
b)[tex] \frac{cos5°+sin25°}{cos25°-sin5°} = \sqrt{3} [/tex]
c)[tex]sin^{4} \frac{ \pi }{8} + sin^{4} \frac{3 \pi }{8} + sin^{4} \frac{5 \pi }{8} + sin^{4} \frac{7 \pi }{8} = \frac{3}{2} [/tex]
d)[tex]cos^{4} \frac{ \pi }{8} + cos^{4} \frac{3 \pi }{8} + cos^{4} \frac{5 \pi }{8} + cos^{4} \frac{7 \pi }{8} = \frac{3}{2} [/tex]
e)[tex]sin20°*sin40°*sin60°*sin80°= \frac{3}{16} [/tex]
Acel A cu caciulita arata ca acolo sunt grade (cos12grade,sin12grade...)si el nu se afla in enunt.
Multumesc mult!