Question

вычислите :
2sin 127°+cos 37° - 8cos 143°/sin 42° * sin 75°+sin 48*sin 15°

Answer 1

$displaystyle frac{2sin127^circ+cos37^circ-8cos143^circ}{sin42^circsin75^circ+sin48^circsin15^circ}=frac{2sin(90^circ+37^circ)+cos37^circ-8cos(180^circ-37^circ)}{sin(90^circ-48^circ)sin(90^circ-15^circ)+sin48^circsin15^circ}=\ \ =frac{2cos37^circ+cos37^circ+8cos37^circ}{cos48^circcos15^circ+sin48^circsin15^circ}=frac{11cos37^circ}{cos(48^circ-15^circ)}=frac{11cos37^circ}{cos33^circ}$