Question

Решите )) заранее : ) 1) 2√3 sin60°+4cos60° 2) √3ctg30°-tg45° 3)2sin30°-√3cos60° ctg45° tg30°

Answer 1

Sin60° = √3/2;      ctg30° = √3;              sin30° = 1/2;
cos60° = 1/2;        tg45° = ctg45° = 1;  tg30° = 1/√3          - нужно выучить!

1) 2√3sin60°+ 4cos60° =2√3 · √3/2 + 4 · 1/2 = 3 + 2 = 5
2) √3ctg30° - tg45° = √3 · √3 - 1 = 3 - 1 = 2
3) 2sin30° - √3cos60°ctg45°tg30° = 2 · 1/2 - √3 · 1/2 · 1 · 1/√3 = 1 - 1/2 = 1/2