How do you express `cos(pi/ 2 ) * cos (( 19 pi) / 12 )` without using products of trigonometric functions?

Related questions

• How do you use linear combinations to solve trigonometric equations?
• How do you derive the multiple angles formula?
• How do you apply trigonometric equations to solve real life problems?
• How do you use the transformation formulas to go from product to sum and sum to product?
• What is the sum to product formulas?
• How do you change `2 \sin 7x \cos 4x` into a sum?
• How do you solve `sin 4x + sin 2x = 0` using the product and sum formulas?
• How do you use the sum and double angle identities to find sin3x?
• How do you simplify `sin^2theta-cos^2theta+tan^2theta` to non-exponential trigonometric functions?
• How do you simplify `sin^2theta` to non-exponential trigonometric functions?