Question

1) sin²30°+ctg²30°
2) 4cos²45°-sin²60°



Дам 20 баллов

Answer 1

Ответ:

1) sin² 30° + ctg² 30°

sin 30° = 1/2

ctg 30° = √3

(1/2)² + (√3)² = 1/4 + 3 = 3 1/4 = 3 25/100 = 3,25

2) 4 cos²45° - sin²60°

cos 45° = √2/2

sin 60° = √3/2

4 × (√2/2)² - (√3/2)² = 4 × 2/4 - 3/4 = 2 - 3/4 = 1 4/4 - 3/4 = 1 1/4 = 1 25/100 = 1,25