cos^(4)A-sin^(4)A=2cos^(2)A-1

Prove the following cos^(4)A-sin^(4)A+1=2cos^(2)A

Prove that cos^(4)A-sin^(4)A=cos^(2)A-sin^(2)A .

If 5sin x =4 , then the numberical value of ((tanx-cotx)/(secx-tanx))((cos^(4)x-sin^(4)x)/(2cos^(2)x-1)) ?

Prove the following identities: sin^(4)A-cos^(4)A=sin^(2)A-cos^(2)A=2sin^(2)A-1=1-2cos^(2)A

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

If sin A+sin^(2)A+sin^(3)A=1, then find the value of cos^(6)A-4cos^(4)A+8cos^(2)A

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

Prove the following identities : (1 - 2 sin^(2) A)^(2)/(cos^(4) A - sin^(4) A) = 2 cos^(2) A - 1

cos^(4)A-sin^(4)A is equal to 2cos^(2)A+1(b)2cos^(2)A-1(c)2sin^(2)A-1( d) 2sin^(2)A+1