Final Answer
Step-by-step Solution
Specify the solving method
I. Express the LHS in terms of sine and cosine and simplify
Start from the LHS (left-hand side)
Learn how to solve trigonometric identities problems step by step online.
Learn how to solve trigonometric identities problems step by step online. Prove the trigonometric identity cos(x-y)+cos(x+y)=2cos(x)cos(y). section:I. Express the LHS in terms of sine and cosine and simplify. Start from the LHS (left-hand side). Using the cosine of a sum formula: \cos(\alpha\pm\beta)=\cos(\alpha)\cos(\beta)\mp\sin(\alpha)\sin(\beta), where angle \alpha equals x, and angle \beta equals y. section:II. Express the RHS in terms of sine and cosine and simplify.