** Final answer to the problem

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** Step-by-step Solution **

** How should I solve this problem?

- Prove from LHS (left-hand side)
- Prove from RHS (right-hand side)
- Express everything into Sine and Cosine
- Exact Differential Equation
- Linear Differential Equation
- Separable Differential Equation
- Homogeneous Differential Equation
- Integrate by partial fractions
- Product of Binomials with Common Term
- FOIL Method
- Load more...

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Starting from the left-hand side (LHS) of the identity

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Since the expression on the left of the equality is too simple, it's not clear how we can proceed to prove the identity from there. Although we know that the identity is true

** Final answer to the problem

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