Question

a) tg75-tg30 дробь 1+tg75 tg30
б)sin80 cos20 - sin20 cos 80

Answer 1

б) $sin80cos20-sin20cos80=sin(80-20)=sin60= \frac{ \sqrt{3} }{2}$

a) $\frac{tg75tg30}{1+tg75tg30}=tg(75-30)=tg45=1$