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Prove the identity: sec4 x – sec2 x = tan4 x + tan2 x |
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Answer» Let us consider the LHS: sec4 x – sec2 x (sec2 x)2 – sec2 x On using the formula, sec2 θ = 1 + tan2 θ. (1 + tan2 x)2 – (1 + tan2 x) 1 + 2tan2 x + tan4 x – 1 – tan2 x tan4 x + tan2 x = RHS ∴ LHS = RHS Thus proved. |
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