2sinx-cosx=0 2sin x=cos x tan x=sin x / cos x =1/2sin2x =2 sin x cos x =(2 sin x cos x ) / (sin^2 x + cos^2 x )=2tan x /(tan^2 x +1) =4/5sin^2 x +sin x cos x =(sin^2 x +sin x cos x) / (sin^2 x + cos^2...