Saved Bookmarks
| 1. |
3. tan 20° cot 70° – sec 20° cosec 70 |
|
Answer» TAN 20°× cot 70° - sec20°×cosec 70° =tan 20°×cot(90°-20°)-sec 20°×cosec(90°-20°) =tan 20°× tan 20°-sec 20°× sec 20° =tan^2 20°-sec^2 20° =-(sec^2 20°- tan^2 20°) =-1 |
|