Prove sin4(x) - cos4(x) = 1 - 2cos2(x)

Here is the step by step demonstrations to prove sin4(x) - cos4(x) = 1 - 2cos2(x) trig identity easily.


Sin4(x) - cos4(x) = 1 - 2cos2(x) - Trig Identities Proof

LHS
= sin4(x) - cos4(x)

= (sin2(x) - cos2(x)) × (sin2(x) + cos2(x))

= sin2(x) - cos2(x)

= 1 - cos2(x) - cos2(x)

= 1 - 2cos2(x)

= RHS

Hence Proved.
Trig identities proof are made simpler and easier here. Listed here various trig identities with the step by step proof.


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