Saved Bookmarks
| 1. |
Prove that :Sin theta -2sin ^3 theta /2 cos^3 theta-cos theta=tan theta |
|
Answer» Sin○-2sin^3○/2cos^3○-cos○ =sin○(1-2sin^2○)/cos○(2cos^2○-1) =sin○(2cos○)/cos (2cos○) Because 2cos^2○-1 and 1-2sin^2○=cos2○ Cut cos2○ and cos2○ Hence sin/cos=tan is proved Sin○-2sin^3○/2cos^3○-cos○=sin○(1-2sin^2○)/cos○(2cos^2○-1)=sin○(2cos○)/cos (2cos○)Because 2cos^2○-1 and 1-2sin^2○=cos2○Cut cos2○ and cos2○NOW,sin/cos=tan○ |
|