Identities for sin2A, cos2A and tan2A

In this video you are shown how the double angle identities are derived from the addition identities

Double angle identities

  •     \begin{align*} \sin{2A} \equiv 2 \sin A \cos A \end{align} \\

        \begin{align*} \cos {2A} &\equiv \cos {^2{A}} - \sin {^2{A}} \\  &\equiv 2 \cos {^2{A}} - 1  \\  &\equiv 1 - 2 \sin {^2{A}} \end{align*} \\

        \begin{align*} \tan {2A} \equiv \dfrac{2 \tan A}{1 - \tan {^2{A}}} \end{align}




2018-08-08T17:47:34+00:00
This website uses cookies and third party services. Settings Ok