Sin 4 a -cos 4 a - sin 2 a + cos 2 a алгебра

Question

Sin 4 a -cos 4 a - sin 2 a + cos 2 a алгебра

Answer 1

2sin2acos6a-2cos2acos6a=2cos6a(sin2a-cos2a)=
=2cos6a(sin2a-sin(π/2-2a))=2cos6a*2sin(2a-π/4)cosπ/4=
=4*√2/2*cos6a*sin(2a-π/4)=2√2cos6a*sin(2a-π/4)

Comments

равно 0=?

Answer 2

(Sin4a-sin2a)+(cos4a-cos2a)=sin2a(sin2a-1)+cos2a(cos2a-1)=i

Comments

равно 0=?