cot 2α + csc 2α
α
is gelijk aan
|
A. sin α |
| B. cos α |
| C. tan α |
| D. cot α |
| E. sec α |
[ 5-7380 - op net sinds 17.12.2025-(E)-16.10.2026 ]
Translation in E N G L I S H
cot 2α + csc 2α
is equal to
|
Oplossing - Solution
\(\large\cot 2\alpha+\csc2\alpha=\frac{1}{\tan 2\alpha}+\frac{1}{\sin 2\alpha}=\frac{1-\tan^2\alpha}{2\tan{\alpha}}+\frac{1}{2\sin{\alpha}\cos{\alpha}}\)
\(\Large=\frac{(1-\tan^2\alpha)\cos\alpha}{2\sin\alpha}+\frac{1}{2\sin\alpha.\cos\alpha}=\frac{(1-\tan^2\alpha)\cos^2\alpha+1}{2\sin\alpha\cos\alpha\alpha}\)
\(\Large=\frac{\cos^2\alpha-\sin^2\alpha+1}{2\sin\alpha\cos\alpha}=\frac{2\cos^2\alpha}{2\sin\alpha\cos\alpha}=\frac{\cos\alpha}{\sin\alpha}=\cot\alpha\)