Question

Cum se calculeaza:
cos pi/3 +sin 2pi/3 -cos 3pi/4 +sin 5pi/6

Answer 1

Swe calculeaz prin reducere l;am, primul cadran

cos π/3=1/2

sin2π/3=sin(π-2π/3)=sin π/3=√3/2

cos 3π/4= -cos(π-3π/4)=-cosπ/4= -√2/2

sin 5π/6=sin(π-5π/5)=sin π/6=1/2

expresia devine

1/2+√3/2+√2/2 +1/2=1+(√3+√2)/2