Question

Вычислите:

а) 2sin60° + ctg ( - π/6)

б) cos 7π/4 + tg540° 

 

 

 

 

Answer 1

1)

$displaystyle 2sin(60)+ctg(-frac{pi}{6})=2*frac{sqrt{3}}{2}- ctg(frac{pi}{6})=sqrt{3}-sqrt{3}=0$

2)

$displaystyle cos(frac{7pi}{4})+tg(540)=cos(pi-frac{pi}{4})+tg(360+180)=\\=cos(frac{pi}{4})+tg(pi)=frac{sqrt{2}}{2}+0=frac{sqrt{2}}{2}$