To prove sin4a-cos4a = 2sin2a-1

Isn't that right
Special value method, take a = π / 8
Then 4A = π / 2, 2A = π / 4
Left = 1
Right = (√ 2) - 1
Obviously, this is not the right time

(1+sin4a-cos4a)/(1+sin4a+cos4a)=?

(1 + sin 4 a - cos 4 a) / (1 + sin 4 a + cos 4 a)= (1 - cos 4 a + sin 4 a) / (1 + cos 4 a + sin 4 a)= (2 sin^2 2 a + 2 sin 2 a cos 2 a)/ (2 cos^2 2 a + 2 sin 2 a cos 2 a)= [2 (sin 2 a) (sin 2 a + cos ...

To prove sin4a-cos4a = 2sin2a-1

To prove sin4a-cos4a = 2sin2a-1

(1+sin4a-cos4a)/(1+sin4a+cos4a)=?

RELATED INFORMATIONS