| Welke gelijkheid is correct ?
|
|---|
| A. sin 20° + 2.sin40° = sin 40° + cos 10° |
| B. sin 20° + 2.sin40° = sin 40° + 2.cos 20° |
| C. sin 20° + 2.sin40° = cos 70° + cos 50° |
| D. sin 20° + 2.sin40° = sin 40° + 2.sin 20° |
| E. sin 20° + 2.sin40° = sin 40° + sin 60° |
[ 5-6789 - op net sinds 30.5.14-(E)-27.10.2023 ]
Translation in E N G L I S H
| Which equality is correct ?
|
|---|
| A. sin 20° + 2.sin40° = sin 40° + cos 10° |
| B. sin 20° + 2.sin40° = sin 40° + 2.cos 20° |
| C. sin 20° + 2.sin40° = cos 70° + cos 50° |
| D. sin 20° + 2.sin40° = sin 40° + 2.sin 20° |
| E. sin 20° + 2.sin40° = sin 40° + sin 60° |
Oplossing - Solution
sin 20° + 2.sin40°
= sin 20° + sin 40° + sin40° (nu SIMPSON)
= 2.sin 30°.cos(−10°) + sin 40°
= cos 10° + sin 40°