Q1. Use the sum-to-product formula to writecos13xcos3xas a product.

• 2sin8xsin5x
• 2sin8xsin5x
• 2cos5xsin8x
• sin16x
• 1/2sin8xsin5x

Q2. Use the product-to-sum formula to writecos3xsin 9x as a sum or difference.

• 1/2cos12x+1/2cos 6x
• 1/2sin12x+1/2sin 6x
• 1/2cos12x1/2cos 6x
• 1/2sin12x1/2sin 6x

Q3. Find the exact value ofcosx/2 givencosx=9/13 and

cosx/2=____________

Q4. Rewrite sin²2tcos²2t without using any powers

• 1/8(1cos8t)
• 1/8(1sin8t)
• 1/8(1cos4t)
• 1/8(1+cos8t)

Q5. Use a double-angle formula to rewrite the expression.

16cos²8

• 8cos2
• 8sin2
• 8sin2
• 8cos2

Q6. Use a double-angle formula to evaluate the expression.

cos (7/2)=