Тригонометрия - сложения
sin(x + y) = sinx•cosy + cosx•siny
sin(x - y) = sinx•cosy - cosx•siny
cos(x + y) = cosx * cosy - sinx * siny
cos(x - y) = cosx * cosy + sinx * siny
tg(x + y) = (tgx + tgy) / (1 - tgx*tgy)
tg(x + y) = (tgx - tgy) / (1 + tgx*tgy)
ctg(x + y) = (1 - ctgx*ctgy) / (ctgx + ctgy)
ctg(x - y) = (1 + ctgx*ctgy) / (ctgx - ctgy)
sin(x + y) = sinx•cosy + cosx•siny sin(x - y) = sinx•cosy - cosx•siny cos(x + y) = cosx * cosy - sinx * siny cos(x - y) = cosx * cosy + sinx * siny tg(x + y) = (tgx + tgy) / (1 - tgx*tgy) tg(x + y) = (tgx - tgy) / (1 + tgx*tgy) ctg(x + y) = (1 - ctgx*ctgy) / (ctgx + ctgy) ctg(x - y) = (1 + ctgx*ctgy) / (ctgx - ctgy)