Question

if tan x = n tan y and sin x = m sin y prove that cos²x = m²-1/n²-1​

Answer 1

                    Answer:

Step-by-step explanation:

tan x / tan y = n  ⇒ n^2 = tan^2 x / tan^2 y

                              n^2 - 1 = tan^2 x - tan^2 y / tan^2y

similarly                  m^2 - 1 = sin^2 x - sin^2 y / sin^2y

m^2 - 1 /  n^2 - 1 =   ( sin^2 x - sin^2 y )( tan^2y)  /   ( tan^2 x - tan^2 y )sin^2y

               =  ( sin^2 x - sin^2 y ) (  1 / cos^2 y )  / sec^2x - sec^2 y

      =   ( sin^2 x - sin^2 y ) (  1 / cos^2 y ) / cos ^2y - cos^2x / cos^2xcos^2y

        = cos^2 x                

Answer 2

Answer:

answer in attachment

Step-by-step explanation:

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