You have seen quite a few trigonometric identities in the past few pages It is convenient to have a summary of them for reference These identities mostly refer to one angle denoted θ, but there are some that involve two angles, and for those, the two angles are denoted α and β The more important identities(1tan^2x)cot^2x=csc^2xcot^2 1 =The figure at the right shows a sector of a circle with radius 1 The sector is θ/(2 π) of the whole circle, so its area is θ/2We assume here that θ < π /2 = = = = The area of triangle OAD is AB/2, or sin(θ)/2The area of triangle OCD is CD/2, or tan(θ)/2 Since triangle OAD lies completely inside the sector, which in turn lies completely inside triangle OCD, we have
What Is The Formula Of Tan2x Quora
