Упростить Cos4a-sin4a - cos2a

cos4a-sin4a-cos2a=cos

2

2a-sin

2

2a-2sin2acos2a-cos2a=

= (/cos^2 a - / sin^2 a) ^2-4/sin^2 a/cos^2 a (/cos^2 a-/sin^2 a) - = (cos

2

a-sin

2

a)

2

-4sin

2

acos

2

a (cos

2

a-sin

2

a) -

- (/cos^2 a-/sin^2 a) = / cos^4 a - 2/sin^2 a / cos^2 a + / sin^4 a - - (cos

2

a-sin

2

a) = cos

4

a-2sin

2

acos

2

a+sin

4

a-

-4/sin^2 a/cos^4 a+4/sin^4 a/cos^2 a-4sin

2

acos

4

a+4sin

4

acos

2

a