Question

Формулы приведения. Ребят, помогите, пожалуйста.

Answer 1

1)-12√3 ctq(-480)=+12√3ctq480=12√3ctq(480-360)=12√3ctq120=12√3ctq(180-60)=12√3ctq(-60)= - 12√3ctq60= - 12√3 · √3 = - 12 · 3 = - 36;
2) 3cos37/sin53 = 3cos37/sin(90-37) =3cos37/cos37 = 3;
3) 3cos(5π+α) - sin(α - 3π/2) = - 3cosα + sin(3π/2 -α) = -3cosα - cosα = - 4cosα;
4) sin(-25π/4) cos(-35π/4)  /2 = -sin(6π+π/4)cos(8π+3π/4)   /2 = - sin π/4 cos3π/4   /2 = - sinπ/4 · cos(π - π/4)  /2 = +sin π/4 · sin π/4  /2 = (√2/2)² /2= (2 /4) /2= (1/2) /2 =1/4;
5) tq(α- 9π/2) = - tq(4π +π/2 - α) = - ctq α = - (-0,3) =0,3