1. cos125° = cos(180° –55°) = - cos 55°
2. sin 5π/6 = sin (π – π/6) = sin π/6
3. sin 70° = sin(90° –20°) = cos 20°
4. cos π/3 = cos(π/2– π/6) = sin π/6
cos 2π/3 = cos (π– π/3) = - cos π/3 = - 1/2
cos 5π/6 = cos (π– π/6) = - cos π/6 = -
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Сos125=cos(180-55)=-cos55sin5π/6=sin(π-π/6)=sinπ/6
sin70=sin(90-20)=cos20
cosπ/3=cos(π/2-π/6)=sinπ/6
cos2π/3=cos(π-π/3)=-cosπ/3
cos5π/6=cos(π-π/6)=-cosπ/6
1. cos125° = cos(180° –55°) = - cos 55°
2. sin 5π/6 = sin (π – π/6) = sin π/6
3. sin 70° = sin(90° –20°) = cos 20°
4. cos π/3 = cos(π/2– π/6) = sin π/6
cos 2π/3 = cos (π– π/3) = - cos π/3 = - 1/2
cos 5π/6 = cos (π– π/6) = - cos π/6 = -