Which sum or difference identity would you use to verify that sin (90° + q) = cos q? a. cos (a -b) = cos a cos b + sin a sin b b. sin (a +b) = sin a cos b + cos a sin b c. sin (a -b) = sin a cos b- cos a sin b d. cos (a +b) = cos a cos b - sin a sin b

Scenario: susan wants to make 2 square flags to sell at a crafts fair. the fabric she wants to buy is 3 meters wide. she doesn't want any fabric left over. what's the least amount of fabric she should buy? question: which equation will susan solve her problem? note: let x represent the length of 1 side of the flag. options: 1) 2x^2 = 4x 2) 8 +2x = 2(4x) 3) 2 * 2 = 4 * 2 4) 4x^2 -2x = 0