Question

Решите (cos100°+cos20°)/sin50°

Answer 1

Ответ:

(cos100°+cos20°)/sin50°=2cos(60°)cos(40°)/sin(50°)=2cos(60°)cos(90°-50°)/sin(50°)= 2cos(60°)cos(50°)/sin(50°)=2cos60°=2×1/2=1

Объяснение:

прошу лучший

Answer 2

$\displaystyle\bf\\\frac{Cos100^\circ+Cos20^\circ}{Sin50^\circ}=\frac{2Cos\frac{100^\circ+20^\circ }{2} Cos\frac{100^\circ-20^\circ }{2} }{Sin50^\circ} =\frac{2Cos60^\circ Cos40^\circ}{Sin(90^\circ-40^\circ) } =\\\\\\=\frac{2\cdot\frac{1}{2} \cdot Cos40^\circ}{Sin40^\circ}=1$