sec4 A sec2 A is equal to

Note: Since all the options involve the trigonometric ratio tan θ, so we use the identity 1 + tan2 θ = sec2 θ.


To find: sec4 A – sec2 A


Consider sec4 A – sec2 A = (sec2 A)2 – sec2 A


Now, as sec2 A = 1 + tan2 A


sec4 A – sec2 A = (sec2 A)2 – sec2 A


= (1 + tan2 A)2 – (1 + tan2 A)


= 1 + tan4 A + 2 tan2 A – 1 – tan2 A


= tan4 A + tan2 A

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