Question

Sa se arate ca:
a)$\frac{cos12+ \sqrt{3}sin12 }{cos3-sin3}= \sqrt{2}$
b)$\frac{cos5+sin25}{cos25-sin5} = \sqrt{3}$
c)$sin^{4} \frac{ \pi }{8} + sin^{4} \frac{ 3\pi }{8} + sin^{4} \frac{5 \pi }{8} + sin^{4} \frac{ 7\pi }{8} = \frac{3}{2}$
d)$cos^{4} \frac{ \pi }{8} + cos^{4} \frac{ 3\pi }{8} + cos^{4} \frac{5 \pi }{8} + cos^{4} \frac{ 7\pi }{8} = \frac{3}{2}$
e)sin20*sin40*sin60*sin80=$\frac{3}{16}$

Answer 1

Rezolvarea se află în poză.