Prove that `(sin^(4)theta-cos^(4)theta)/(sin^(2)theta-cos^(2)theta)=1`

Prove that : sin^(4)theta-cos^(4)theta=2sin^(2)theta-1

sin^(4)theta+cos^(4)theta=1-2sin^(2)theta cos^(2)theta

Prove that (cos^(4)theta-sin^(4)theta)/(cos^(2)theta-sin^(2)theta)=1

Prove that 2cos^(2)theta-cos^(4)theta+sin^(4)theta=1

Prove that : sin^(2)theta+cos^(4)theta=cos^(2)theta+sin^(4)theta

Prove the following identities: 2(sin^(6)theta+cos^(6)theta)-3(sin^(4)theta+cos^(4)theta)+1=0sin^(6)theta+cos^(6)theta+3sin^(2)theta cos^(2)theta=1(sin^(8)theta-cos^(8)theta)=(sin^(2)theta-cos^(2)theta)(1-2sin^(2)theta cos^(2)theta)

Prove : 2(sin^(6)theta+cos^(6)theta)-3(sin^(4)theta+cos^(4)theta)+1=0 .

sec^(2)theta-(sin^(2)theta-2sin^(4)theta)/(2cos^(4)theta-cos^(2)theta)=1

Prove that : cos^(4)theta - cos^(2)theta = sin^(4)theta - sin^(2) theta

The value for 2(sin^(6)theta+cos^(6)theta)-3(sin^(4)theta+cos^(4)theta)+1 is