Ответы и объяснения

2014-01-02T10:15:58+00:00
1 + tg²x = 1/cos²x
tg²x = 1/cos²x - 1 = 1/0.6 - 1 = 10/6 - 1 = (10-6) / 6 = 4/6 = 2/3
2+3tg²x = 2+3*2/3 = 2+2=4