Question

Найдите значение выражения 17sin20°/cos10°*cos80°

Answer 1

$\displaystyle\bf\\\frac{17Sin20^\circ}{Cos10^\circ\cdot Cos80^\circ } =\frac{17\cdot 2Sin10^\circ Cos10^\circ }{Cos10^\circ\cdot Cos(90^\circ-10^\circ) } =\frac{34Sin10^\circ}{Sin10^\circ}=34$