Вычислить :
1) sin 120
2 ) cos 210
3) sin 20 * cos 25 + sin 25 * cos 20
1) sin 120
2 ) cos 210
3) sin 20 * cos 25 + sin 25 * cos 20
More Questions From This User See All
Copyright © 2024 SCHOLAR.TIPS - All rights reserved.
Answers & Comments
Verified answer
1) sin120= sin(90 + 30) = sin90cos30 + cos90sin30 = 1*√3/2 + 0*1/2 = √3/2
2) cos210= cos(180 + 30) = cos180cos30 – sin180sin30 = (-1)* √3/2 – 0*1/2 = -√3/2
3) sin20cos25+ cos20sin25 = sin(20 + 25) = sin45 = √2/2