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using the formula of Sin 2A ,cos2a and tan 2a establish that; tab A is = +- root under 1 - cos 2A by 1 + cos 2a​

Using The Formula Of Sin 2A Cos2a And Tan 2a Establish That Tab A Is Root Under 1 Cos 2A By 1 Cos 2a class=

Sagot :

Answer:

Step-by-step explanation:

Given identity is,

[tex]\text{tanA}=\pm\sqrt{\frac{1-\text{cos2A}}{1+\text{cos2A}}}[/tex]

To prove this identity, we will take left side of the identity,

[tex]\pm\sqrt{\frac{1-\text{cos2A}}{1+\text{cos2A}}}=\pm\sqrt{\frac{1-(1-2\text{sin}^2A)}{1+(2\text{cos}^2A-1)} }[/tex]

                  [tex]=\pm\sqrt{\frac{1-1+2\text{sin}^2A}{1+2\text{cos}^2A-1} }[/tex]

                  [tex]=\pm\sqrt{\frac{2\text{sin}^2A}{2\text{cos}^2A} }[/tex]

                  [tex]=\pm(\sqrt{\text{tan}^2A})[/tex]

                  [tex]=\text{tanA}[/tex] [Right side of the identity]

Hence, proved.