Respuestas

2013-09-10T02:55:10+02:00
tan(x y) = (tan x tan y) / (1  tan x tan y)sen(2x) = 2 sen x cos xcos(2x) = cos^2(x) - sen^2(x) = 2 cos^2(x) - 1 = 1 - 2 sen^2(x)tan(2x) = 2 tan(x) / (1 - tan^2(x))sen^2(x) = 1/2 - 1/2 cos(2x)cos^2(x) = 1/2 + 1/2 cos(2x)sen x - sen y = 2 sen( (x - y)/2 ) cos( (x + y)/2 )cos x - cos y = -2 sen( (x-y)/2 ) sen( (x + y)/2 )