# Precalculus

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1. What two common identities are most useful for simplifying 2tanx/(sin^2x + cos^2x - tan^2x)?

Two identities are: sin^2x + cos^2x = 1 and tan2x=2tanx/1-tan^2x

• Precalculus -

2tanx/(sin^2x + cos^2x - tan^2x)
= 2tanx/(1 - tan^2 x)
= tan(2x)

• Precalculus -

Thank you~

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