Tan a * cot a - cos2 a (Cos a - sin a )2 + ( cos a + sin a)2+1

Question

Tan a * cot a - cos2 a
(Cos a - sin a )2 + ( cos a + sin a)2+1

Answer 1

Раскрываем скобки:
2cos a - 2sin a + 2cos a + 2sin a + 1 = 4cos a = -1
cos a = - 0.25